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| Product NDC Code | 68071-3012 | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Drug Name | Topiramate |
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| Type | Generic | ||||||||
| Pharm Class | Cytochrome P450 2C19 Inhibitors [MoA], Cytochrome P450 3A4 Inducers [MoA], Decreased Central Nervous System Disorganized Electrical Activity [PE] |
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| Active Ingredients |
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| Route | ORAL | ||||||||
| Dosage Form | TABLET, FILM COATED | ||||||||
| RxCUI drug identifier | 199888 | ||||||||
| Application Number | ANDA090278 | ||||||||
| Labeler Name | NuCare Pharmaceuticals, Inc. | ||||||||
| Packages |
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Overdosage of Topiramate
Information about signs, symptoms, and laboratory findings of acute ovedosage and the general principles of overdose treatment.10 OVERDOSAGE Overdoses of topiramate have been reported. Signs and symptoms included convulsions, drowsiness, speech disturbance, blurred vision, diplopia, mentation impaired, lethargy, abnormal coordination, stupor, hypotension, abdominal pain, agitation, dizziness and depression. The clinical consequences were not severe in most cases, but deaths have been reported after poly-drug overdoses involving topiramate. Topiramate overdose has resulted in severe metabolic acidosis [see Warnings and Precautions ( 5.4 )] . A patient who ingested a dose between 96 g and 110 g topiramate was admitted to a hospital with a coma lasting 20 to 24 hours followed by full recovery after 3 to 4 days. In acute topiramate overdose, if the ingestion is recent, the stomach should be emptied immediately by lavage or by induction of emesis. Activated charcoal has been shown to adsorb topiramate in vitro . Treatment should be appropriately supportive. Hemodialysis is an effective means of removing topiramate from the body.
Adverse reactions
Information about undesirable effects, reasonably associated with use of the drug, that may occur as part of the pharmacological action of the drug or may be unpredictable in its occurrence. Adverse reactions include those that occur with the drug, and if applicable, with drugs in the same pharmacologically active and chemically related class. There is considerable variation in the listing of adverse reactions. They may be categorized by organ system, by severity of reaction, by frequency, by toxicological mechanism, or by a combination of these.6 ADVERSE REACTIONS The following serious adverse reactions are discussed in more detail in other sections of the labeling: • Acute Myopia and Secondary Angle Closure Glaucoma [see Warnings and Precautions (5.1)] • Visual Field Defects [see Warnings and Precautions (5.2)] • Oligohidrosis and Hyperthermia [see Warnings and Precautions (5.3)] • Metabolic Acidosis [see Warnings and Precautions (5.4)] • Suicidal Behavior and Ideation [see Warnings and Precautions (5.5)] • Cognitive/Neuropsychiatric Adverse Reactions [see Warnings and Precautions (5.6)] • Hyperammonemia and Encephalopathy (Without and With Concomitant Valproic Acid [VPA] Use) [see Warnings and Precautions (5.9)] • Kidney Stones [see Warnings and Precautions (5.10)] • Hypothermia with Concomitant Valproic Acid (VPA) Use [see Warnings and Precautions (5.11)] The data described in the following sections were obtained using topiramate tablets. Epilepsy: Most common (≥10% more frequent than placebo or low-dose topiramate) adverse reactions in adult and pediatric patients were: paresthesia, anorexia, weight loss, speech disorders/related speech problems, fatigue, dizziness, somnolence, nervousness, psychomotor slowing, abnormal vision and fever (6.1) Migraine: Most common (≥5% more frequent than placebo) adverse reactions in adult and pediatric patients were: paresthesia, anorexia, weight loss, difficulty with memory, taste perversion, diarrhea, hypoesthesia, nausea, abdominal pain and upper respiratory tract infection (6.1) To report SUSPECTED ADVERSE REACTIONS, contact Sun Pharmaceutical Industries, Inc. at 1-800-818-4555 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, the incidence of adverse reactions observed in the clinical trials of a drug cannot be directly compared to the incidence of adverse reactions in the clinical trials of another drug, and may not reflect the incidence of adverse reactions observed in practice. Monotherapy Epilepsy Adults 16 Years of Age and Older The most common adverse reactions in the controlled clinical trial (Study 1) that occurred in adults in the 400 mg/day topiramate group and at an incidence higher (≥ 10 %) than in the 50 mg/day group were: paresthesia, weight loss and anorexia (see Table 5). Approximately 21% of the 159 adult patients in the 400 mg/day group who received topiramate as monotherapy in Study 1 discontinued therapy due to adverse reactions. The most common (≥ 2% more frequent than low-dose 50 mg/day topiramate) adverse reactions causing discontinuation were difficulty with memory, fatigue, asthenia, insomnia, somnolence, and paresthesia. Pediatric Patients 6 to 15 Years of Age The most common adverse reactions in the controlled clinical trial (Study 1) that occurred in pediatric patients in the 400 mg/day topiramate group and at an incidence higher (≥10%) than in the 50 mg/day group were fever and weight loss (see Table 5). Approximately 14% of the 77 pediatric patients in the 400 mg/day group who received topiramate as monotherapy in the controlled clinical trial discontinued therapy due to adverse reactions. The most common (≥2% more frequent than low-dose 50 mg/day topiramate) adverse reactions resulting in discontinuation were difficulty with concentration/attention, fever, flushing, and confusion. Table 5 presents the incidence of adverse reactions occurring in at least 3% of adult and pediatric patients treated with 400 mg/day topiramate and occurring with greater incidence than 50 mg/day topiramate. Table 5: Adverse Reactions in the High Dose Group As Compared to the Low Dose Group, in Monotherapy Epilepsy Trial (Study 1) in Adult and Pediatric Patients B od y System Adverse Reaction Age Group Pediatric (6 to 15 Years) Adult (Age ≥16 Years) Topiramate Daily Dosage Group (mg/day) 50 400 50 400 (N=74) % (N=77) % (N=160) % (N=159) % B od y as a Whole - General Disorders Asthenia 0 3 4 6 Fever 1 12 Leg pain 2 3 Central & Peripheral Nervous System Disorders Paresthesia 3 12 21 40 Dizziness 13 14 Ataxia 3 4 Hypoesthesia 4 5 Hypertonia 0 3 Involuntary muscle contractions 0 3 Vertigo 0 3 G a stro-Intestinal System Disorders Constipation 1 4 Diarrhea 8 9 Gastritis 0 3 Dry mouth 1 3 Liver and Biliary System Disorders Increase in Gamma-GT 1 3 M e tabolic and Nutritional Disorders Weight loss 7 17 6 17 Platelet, Bleeding & Clotting Disorders Epistaxis 0 4 Psychiatric Disorders Anorexia 4 14 Anxiety 4 6 Cognitive problems 1 6 1 4 Confusion 0 3 Depression 0 3 7 9 Difficulty with concentration or attention 7 10 7 8 Difficulty with memory 1 3 6 11 Insomnia 8 9 Decrease in libido 0 3 Mood problems 1 8 2 5 Personality disorder (behavior problems) 0 3 Psychomotor slowing 3 5 Somnolence 10 15 Red Blood Cell Disorders Anemia 1 3 Reproductive Disorders, Female Intermenstrual bleeding 0 3 Vaginal hemorrhage 0 3 Resistance Mechanism Disorders Infection 3 8 2 3 Viral infection 3 6 6 8 Respiratory System Disorders Bronchitis 1 5 3 4 Upper respiratory tract infection 16 18 Rhinitis 5 6 2 4 Sinusitis 1 4 Skin and Appendages Disorders Alopecia 1 4 3 4 Pruritus 1 4 Rash 3 4 1 4 Acne 2 3 Special Senses Other, Disorders Taste perversion 3 5 Urinary System Disorders Cystitis 1 3 Micturition frequency 0 3 Renal calculus 0 3 Urinary incontinence 1 3 Vascular (Extracardiac) Disorders Flushing 0 5 Adjunctive Therapy Epilepsy Adults 16 Years of Age and Older In pooled controlled clinical trials in adults with partial-onset seizures, primary generalized tonic- clonic seizures, or Lennox-Gastaut syndrome, 183 patients received adjunctive therapy with topiramate at dosages of 200 to 400 mg/day (recommended dosage range) and 291 patients received placebo. Patients in these trials were receiving 1 to 2 concomitant antiepileptic drugs in addition to topiramate or placebo. The most common adverse reactions in the controlled clinical trial that occurred in adult patients in the 200 to 400 mg/day topiramate group with an incidence higher (≥ 10 %) than in the placebo group were: dizziness, speech disorders/related speech problems, somnolence, nervousness, psychomotor slowing, and vision abnormal (Table 6). Table 6 presents the incidence of adverse reactions occurring in at least 3% of adult patients treated with 200 to 400 mg/day topiramate and was greater than placebo incidence. The incidence of some adverse reactions (e.g., fatigue, dizziness, paresthesia, language problems, psychomotor slowing, depression, difficulty with concentration/attention, mood problems) was dose-related and much greater at higher than recommended topiramate dosing (i.e., 600 mg to 1000 mg daily) compared to the incidence of these adverse reactions at the recommended dosing (200 mg to 400 mg daily) range. Table 6: Most Common Adverse Reactions in Pooled Placebo-Controlled, Adjunctive Epilepsy Trials in Adults a Body System Adverse Reaction Placebo (N=291) Topiramate Dosage (mg/day) 200 to 400 (N=183) Body as a Whole-General Disorders Fatigue 13 15 Asthenia 1 6 Back pain 4 5 Chest pain 3 4 Influenza-like symptoms 2 3 Central & Peripheral Nervous System Disorders Dizziness 15 25 Ataxia 7 16 Speech disorders/Related speech problems 2 13 Paresthesia 4 11 Nystagmus 7 10 Tremor 6 9 Language problems 1 6 Coordination abnormal 2 4 Gait abnormal 1 3 Gastro-Intestinal System Disorders Nausea 8 10 Dyspepsia 6 7 Abdominal pain 4 6 Constipation 2 4 Metabolic and Nutritional Disorders Weight loss 3 9 Psychiatric Disorders Somnolence 12 29 Nervousness 6 16 Psychomotor slowing 2 13 Difficulty with memory 3 12 Confusion 5 11 Anorexia 4 10 Difficulty with concentration/attention 2 6 Mood problems 2 4 Agitation 2 3 Aggressive reaction 2 3 Emotional lability 1 3 Cognitive problems 1 3 Reproductive Disorders Breast pain 2 4 Respiratory System Disorders Rhinitis 6 7 Pharyngitis 2 6 Sinusitis 4 5 Vision Disorders Vision abnormal 2 13 Diplopia 5 10 a Patients in these adjunctive trials were receiving 1 to 2 concomitant antiepileptic drugs in addition to topiramate or placebo. In controlled clinical trials in adults, 11% of patients receiving topiramate 200 to 400 mg/day as adjunctive therapy discontinued due to adverse reactions. This rate appeared to increase at dosages above 400 mg/day. Adverse reactions associated with discontinuing topiramate included somnolence, dizziness, anxiety, difficulty with concentration or attention, fatigue and paresthesia. Pediatric Patients 2 to 15 Years of Age In pooled, controlled clinical trials in pediatric patients (2 to 15 years of age) with partial-onset seizures, primary generalized tonic-clonic seizures, or Lennox-Gastaut syndrome, 98 patients received adjunctive therapy with topiramate at dosages of 5 to 9 mg/kg/day (recommended dose range) and 101 patients received placebo. The most common adverse reactions in the controlled clinical trial that occurred in pediatric patients in the 5 mg to 9 mg/kg/day topiramate group with an incidence higher (≥ 10 %) than in the placebo group were: fatigue and somnolence (Table 7). Table 7 presents the incidence of adverse reactions that occurred in at least 3% of pediatric patients 2 to 15 years of age receiving 5 mg to 9 mg/kg/day (recommended dose range) of topiramate and was greater than placebo incidence. Table 7: Adverse Reactions in Pooled Placebo-Controlled, Adjunctive Epilepsy Trials in Pediatric Patients 2 to 15 Years of Age a,b Body System/ Adverse Reaction Placebo (N=101) % Topiramate (N=98) % Body as a Whole - General Disorders Fatigue 5 16 Injury 13 14 Central & Peripheral Nervous System Disorders Gait abnormal 5 8 Ataxia 2 6 Hyperkinesia 4 5 Dizziness 2 4 Speech disorders/Related speech problems 2 4 Gastro-Intestinal System Disorders Nausea 5 6 Saliva increased 4 6 Constipation 4 5 Gastroenteritis 2 3 Metabolic and Nutritional Disorders Weight loss 1 9 Platelet, Bleeding, & Clotting Disorders Purpura 4 8 Epistaxis 1 4 Psychiatric Disorders Somnolence 16 26 Anorexia 15 24 Nervousness 7 14 Personality disorder (behavior problems) 9 11 Difficulty with concentration/attention 2 10 Aggressive reaction 4 9 Insomnia 7 8 Difficulty with memory 0 5 Confusion 3 4 Psychomotor slowing 2 3 Resistance Mechanism Disorders Infection viral 3 7 Respiratory System Disorders Pneumonia 1 5 Skin and Appendages Disorders Skin disorder 2 3 Urinary System Disorders Urinary incontinence 2 4 a Patients in these adjunctive trials were receiving 1 to 2 concomitant antiepileptic drugs in addition to topiramate or placebo. b Values represent the percentage of patients reporting a given adverse reaction. Patients may have reported more than one adverse reaction during the study and can be included in more than one adverse reaction category. None of the pediatric patients who received topiramate adjunctive therapy at 5 to 9 mg/kg/day in controlled clinical trials discontinued due to adverse reactions. Migraine Adults In the four multicenter, randomized, double-blind, placebo-controlled, parallel group migraine clinical trials for the preventive treatment of migraine (which included 35 pediatric patients 12 to 15 years of age), most adverse reactions occurred more frequently during the titration period than during the maintenance period. The most common adverse reactions with topiramate 100 mg in the clinical trials for the preventive treatment of migraine of predominantly adults that were seen at an incidence higher (≥ 5 %) than in the placebo group were: paresthesia, anorexia, weight loss, taste perversion, diarrhea, difficulty with memory, hypoesthesia, and nausea (see Table 8). Table 8 includes those adverse reactions that occurred in the placebo-controlled trials where the incidence in any topiramate treatment group was at least 3% and was greater than that for placebo patients. The incidence of some adverse reactions (e.g., fatigue, dizziness, somnolence, difficulty with memory, difficulty with concentration/attention) was dose-related and greater at higher than recommended topiramate dosing (200 mg daily) compared to the incidence of these adverse reactions at the recommended dosing (100 mg daily). Table 8: Adverse Reactions in Pooled, Placebo-Controlled, Migraine Trials in Adults a,b Body System/ Adverse Reaction Placebo (N=445)% Topiramate Dosage (mg/day) 50 (N=235) % 100 (N=386) % Body as a Whole-General Disorders Fatigue 11 14 15 Injury 7 9 6 Central & Peripheral Nervous System Disorders Paresthesia 6 35 51 Dizziness 10 8 9 Hypoesthesia 2 6 7 Language problems 2 7 6 Gastro-Intestinal System Disorders Nausea 8 9 13 Diarrhea 4 9 11 Abdominal pain 5 6 6 Dyspepsia 3 4 5 Dry mouth 2 2 3 Gastroenteritis 1 3 3 Metabolic and Nutritional Disorders Weight loss 1 6 9 Musculoskeletal System Disorders Arthralgia 2 7 3 Psychiatric Disorders Anorexia 6 9 15 Somnolence 5 8 7 Difficulty with memory 2 7 7 Insomnia 5 6 7 Difficulty with concentration/attention 2 3 6 Mood problems 2 3 6 Anxiety 3 4 5 Depression 4 3 4 Nervousness 2 4 4 Confusion 2 2 3 Psychomotor slowing 1 3 2 Reproductive Disorders, Female Menstrual disorder 2 3 2 Reproductive Disorders, Male Ejaculation premature 0 3 0 Resistance Mechanism Disorders Viral infection 3 4 4 Respiratory System Disorders Upper respiratory tract infection 12 13 14 Sinusitis 6 10 6 Pharyngitis 4 5 6 Coughing 2 2 4 Bronchitis 2 3 3 Dyspnea 2 1 3 Skin and Appendages Disorders Pruritis 2 4 2 Special Sense Other, Disorders Taste perversion 1 15 8 Urinary System Disorders Urinary tract infection 2 4 2 Vision Disorders Blurred vision c 2 4 2 a Includes 35 adolescent patients age 12 to 15 years. b Values represent the percentage of patients reporting a given adverse reaction. Patients may have reported more than one adverse reaction during the study and can be included in more than one adverse reaction category. c Blurred vision was the most common term considered as vision abnormal. Blurred vision was an included term that accounted for >50% of reactions coded as vision abnormal, a preferred term. Of the 1,135 patients exposed to topiramate in the adult placebo-controlled studies, 25% of topiramate-treated patients discontinued due to adverse reactions, compared to 10% of the 445 placebo-treated patients. The adverse reactions associated with discontinuing therapy in the topiramate-treated patients included paresthesia (7%), fatigue (4%), nausea (4%), difficulty with concentration/attention (3%), insomnia (3%), anorexia (2%), and dizziness (2%). Patients treated with topiramate experienced mean percent reductions in body weight that were dose-dependent. This change was not seen in the placebo group. Mean changes of 0%, -2%, -3%, and -4% were seen for the placebo group, topiramate 50, 100, and 200 mg groups, respectively. Pediatric Patients 12 to 17 Years of Age In five, randomized, double-blind, placebo-controlled, parallel group clinical trials for the preventive treatment of migraine, most adverse reactions occurred more frequently during the titration period than during the maintenance period. Among adverse reactions with onset during titration, approximately half persisted into the maintenance period. In four, fixed-dose, double-blind clinical trials for the preventive treatment of migraine in topiramate-treated pediatric patients 12 to 17 years of age, the most common adverse reactions with topiramate 100 mg that were seen at an incidence higher (≥5%) than in the placebo group were: paresthesia, upper respiratory tract infection, anorexia, and abdominal pain (see Table 9). Table 9 shows adverse reactions from the pediatric trial (Study 13 [see Clinical Studies (14.3)] ) in which 103 pediatric patients were treated with placebo or 50 mg or 100 mg of topiramate, and three predominantly adult trials in which 49 pediatric patients (12 to 17 years of age) were treated with placebo or 50 mg, 100 mg or 200 mg of topiramate. Table 9 also shows adverse reactions in pediatric patients in the controlled migraine trials when the incidence in a topiramate dose group was at least 5 % or higher and greater than the incidence of placebo. Many adverse reactions shown in Table 9 indicate a dose-dependent relationship. The incidence of some adverse reactions (e.g., allergy, fatigue, headache, anorexia, insomnia, somnolence, and viral infection) was dose-related and greater at higher than recommended topiramate dosing (200 mg daily) compared to the incidence of these adverse reactions at the recommended dosing (100 mg daily). Table 9: Adverse Reactions in Pooled Double-Blind Studies for the Preventive Treatment of Migraine in Pediatric Patients 12 to 17 Years of Age a,b,c Body System/ Adverse Reaction Placebo (N=45)% Topiramate Dosage 50 mg/day (N=46) % 100 mg/day (N=48) % Body as a Whole-General Disorders Fatigue 7 7 8 Fever 2 4 6 Central & Peripheral Nervous System Disorders Paresthesia 7 20 19 Dizziness 4 4 6 Gastrointestinal System Disorders Abdominal pain 9 7 15 Nausea 4 4 8 Metabolic and Nutritional Disorders Weight loss 2 7 4 Psychiatric Disorders Anorexia 4 9 10 Somnolence 2 2 6 Insomnia 2 9 2 Resistance Mechanism Disorders Infection viral 4 4 8 Respiratory System Disorders Upper respiratory tract infection 11 26 23 Rhinitis 2 7 6 Sinusitis 2 9 4 Coughing 0 7 2 Special Senses Other, Disorders Taste perversion 2 2 6 Vision Disorders Conjunctivitis 4 7 4 a 35 adolescent patients aged 12 to <16 years were also included in adverse reaction assessment for adults (Tables 10 and 11) b Incidence is based on the number of subjects experiencing at least 1 adverse event, not the number of events. c Included studies MIG-3006, MIGR-001, MIGR-002 and MIGR-003 In the double-blind placebo-controlled studies, adverse reactions led to discontinuation of treatment in 8% of placebo patients compared with 6% of topiramate-treated patients. Adverse reactions associated with discontinuing therapy that occurred in more than one topiramate-treated patient were fatigue (1%), headache (1%), and somnolence (1%). Increased Risk for Bleeding Topiramate is associated with an increased risk for bleeding. In a pooled analysis of placebo-controlled studies of approved and unapproved indications, bleeding was more frequently reported as an adverse reaction for topiramate than for placebo (4.5% versus 3.0% in adult patients, and 4.4% versus 2.3% in pediatric patients). In this analysis, the incidence of serious bleeding events for topiramate and placebo was 0.3% versus 0.2% for adult patients, and 0.4% versus 0% for pediatric patients. Adverse bleeding reactions reported with topiramate ranged from mild epistaxis, ecchymosis, and increased menstrual bleeding to life-threatening hemorrhages. In patients with serious bleeding events, conditions that increased the risk for bleeding were often present, or patients were often taking drugs that cause thrombocytopenia (other antiepileptic drugs) or affect platelet function or coagulation (e.g., aspirin, nonsteroidal anti-inflammatory drugs, selective serotonin reuptake inhibitors, or warfarin or other anticoagulants). Other Adverse Reactions Observed During Clinical Trials Other adverse reactions seen during clinical trials were: abnormal coordination, eosinophilia, gingival bleeding, hematuria, hypotension, myalgia, myopia, postural hypotension, scotoma, suicide attempt, syncope, and visual field defect. Laboratory Test Abnormalities Adult Patients In addition to changes in serum bicarbonate (i.e., metabolic acidosis), sodium chloride and ammonia, topiramate was associated with changes in several clinical laboratory analytes in randomized, double-blind, placebo-controlled studies [see Warnings and Precautions (5.4, 5.9)]. Controlled trials of adjunctive topiramate treatment of adults for partial-onset seizures showed an increased incidence of markedly decreased serum phosphorus (6% topiramate versus 2% placebo), markedly increased serum alkaline phosphatase (3% topiramate versus 1% placebo), and decreased serum potassium (0.4 % topiramate versus 0.1 % placebo). Pediatric Patients In pediatric patients (1 to 24 months) receiving adjunctive topiramate for partial-onset seizures, there was an increased incidence for an increased result (relative to normal analyte reference range) associated with topiramate (vs placebo) for the following clinical laboratory analytes: creatinine, BUN, alkaline phosphatase, and total protein, The incidence was also increased for a decreased result for bicarbonate (i.e., metabolic acidosis), and potassium with topiramate (vs placebo) [see Use in Specific Populations (8.4)]. Topiramate is not indicated for partial-onset seizures in pediatric patients less than 2 years of age. In pediatric patients (ranging from 6 to 17 years of age) receiving topiramate for the preventive treatment of migraine, there was an increased incidence for an increased result (relative to normal analyte reference range) associated with topiramate (vs placebo) for the following clinical laboratory analytes: creatinine, BUN, uric acid, chloride, ammonia, alkaline phosphatase, total protein, platelets, and eosinophils, The incidence was also increased for a decreased result for phosphorus, bicarbonate, total white blood count, and neutrophils [see Use in Specific Populations (8.4 )]. Topiramate is not indicated for the preventive treatment of migraine in pediatric patients less than 12 years of age. 6.2 Postmarketing and Other Experience In addition to the adverse experiences reported during clinical testing of topiramate, the following adverse experiences have been reported worldwide in patients receiving topiramate post-approval. These adverse experiences have not been listed above and data are insufficient to support an estimate of their incidence or to establish causation. The listing is alphabetized: bullous skin reactions (including erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis), hepatic failure (including fatalities), hepatitis, maculopathy, pancreatitis, and pemphigus.
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| Pediatric (6 to 15 Years) | Adult (Age ≥16 Years) | |||
| (N=74) % | (N=77) % | (N=160) % | (N=159) % | |
| Asthenia | 0 | 3 | 4 | 6 |
| Fever | 1 | 12 | ||
| Leg pain | 2 | 3 | ||
| Paresthesia | 3 | 12 | 21 | 40 |
| Dizziness | 13 | 14 | ||
| Ataxia | 3 | 4 | ||
| Hypoesthesia | 4 | 5 | ||
| Hypertonia | 0 | 3 | ||
| Involuntary muscle contractions | 0 | 3 | ||
| Vertigo | 0 | 3 | ||
| Constipation | 1 | 4 | ||
| Diarrhea | 8 | 9 | ||
| Gastritis | 0 | 3 | ||
| Dry mouth | 1 | 3 | ||
| Increase in Gamma-GT | 1 | 3 | ||
| Weight loss | 7 | 17 | 6 | 17 |
| Epistaxis | 0 | 4 | ||
| Anorexia | 4 | 14 | ||
| Anxiety | 4 | 6 | ||
| Cognitive problems | 1 | 6 | 1 | 4 |
| Confusion | 0 | 3 | ||
| Depression | 0 | 3 | 7 | 9 |
| Difficulty with concentration or attention | 7 | 10 | 7 | 8 |
| Difficulty with memory | 1 | 3 | 6 | 11 |
| Insomnia | 8 | 9 | ||
| Decrease in libido | 0 | 3 | ||
| Mood problems | 1 | 8 | 2 | 5 |
| Personality disorder (behavior problems) | 0 | 3 | ||
| Psychomotor slowing | 3 | 5 | ||
| Somnolence | 10 | 15 | ||
| Anemia | 1 | 3 | ||
| Intermenstrual bleeding | 0 | 3 | ||
| Vaginal hemorrhage | 0 | 3 | ||
| Infection | 3 | 8 | 2 | 3 |
| Viral infection | 3 | 6 | 6 | 8 |
| Bronchitis | 1 | 5 | 3 | 4 |
| Upper respiratory tract infection | 16 | 18 | ||
| Rhinitis | 5 | 6 | 2 | 4 |
| Sinusitis | 1 | 4 | ||
| Alopecia | 1 | 4 | 3 | 4 |
| Pruritus | 1 | 4 | ||
| Rash | 3 | 4 | 1 | 4 |
| Acne | 2 | 3 | ||
| Taste perversion | 3 | 5 | ||
| Cystitis | 1 | 3 | ||
| Micturition frequency | 0 | 3 | ||
| Renal calculus | 0 | 3 | ||
| Urinary incontinence | 1 | 3 | ||
| Flushing | 0 | 5 | ||
| Placebo (N=291) | Topiramate Dosage (mg/day) 200 to 400 (N=183) | |
| Fatigue | 13 | 15 |
| Asthenia | 1 | 6 |
| Back pain | 4 | 5 |
| Chest pain | 3 | 4 |
| Influenza-like symptoms | 2 | 3 |
| Dizziness | 15 | 25 |
| Ataxia | 7 | 16 |
| Speech disorders/Related speech problems | 2 | 13 |
| Paresthesia | 4 | 11 |
| Nystagmus | 7 | 10 |
| Tremor | 6 | 9 |
| Language problems | 1 | 6 |
| Coordination abnormal | 2 | 4 |
| Gait abnormal | 1 | 3 |
| Nausea | 8 | 10 |
| Dyspepsia | 6 | 7 |
| Abdominal pain | 4 | 6 |
| Constipation | 2 | 4 |
| Weight loss | 3 | 9 |
| Somnolence | 12 | 29 |
| Nervousness | 6 | 16 |
| Psychomotor slowing | 2 | 13 |
| Difficulty with memory | 3 | 12 |
| Confusion | 5 | 11 |
| Anorexia | 4 | 10 |
| Difficulty with concentration/attention | 2 | 6 |
| Mood problems | 2 | 4 |
| Agitation | 2 | 3 |
| Aggressive reaction | 2 | 3 |
| Emotional lability | 1 | 3 |
| Cognitive problems | 1 | 3 |
| Breast pain | 2 | 4 |
| Rhinitis | 6 | 7 |
| Pharyngitis | 2 | 6 |
| Sinusitis | 4 | 5 |
| Vision abnormal | 2 | 13 |
| Diplopia | 5 | 10 |
| a Patients in these adjunctive trials were receiving 1 to 2 concomitant antiepileptic drugs in addition to topiramate or placebo. | ||
| Placebo (N=101) % | Topiramate (N=98) % | |
| | ||
| Fatigue | 5 | 16 |
| Injury | 13 | 14 |
| | ||
| Gait abnormal | 5 | 8 |
| Ataxia | 2 | 6 |
| Hyperkinesia | 4 | 5 |
| Dizziness | 2 | 4 |
| Speech disorders/Related speech problems | 2 | 4 |
| | ||
| Nausea | 5 | 6 |
| Saliva increased | 4 | 6 |
| Constipation | 4 | 5 |
| Gastroenteritis | 2 | 3 |
| | ||
| Weight loss | 1 | 9 |
| Platelet, Bleeding, & Clotting Disorders | ||
| Purpura | 4 | 8 |
| Epistaxis | 1 | 4 |
| | ||
| Somnolence | 16 | 26 |
| Anorexia | 15 | 24 |
| Nervousness | 7 | 14 |
| Personality disorder (behavior problems) | 9 | 11 |
| Difficulty with concentration/attention | 2 | 10 |
| Aggressive reaction | 4 | 9 |
| Insomnia | 7 | 8 |
| Difficulty with memory | 0 | 5 |
| Confusion | 3 | 4 |
| Psychomotor slowing | 2 | 3 |
| | ||
| Infection viral | 3 | 7 |
| | ||
| Pneumonia | 1 | 5 |
| | ||
| Skin disorder | 2 | 3 |
| | ||
| Urinary incontinence | 2 | 4 |
| a Patients in these adjunctive trials were receiving 1 to 2 concomitant antiepileptic drugs in addition to topiramate or placebo. b Values represent the percentage of patients reporting a given adverse reaction. Patients may have reported more than one adverse reaction during the study and can be included in more than one adverse reaction category. | ||
| Placebo (N=445)% | Topiramate Dosage (mg/day) | ||
| 50 (N=235) % | 100 (N=386) % | ||
| | |||
| Fatigue | 11 | 14 | 15 |
| Injury | 7 | 9 | 6 |
| | |||
| Paresthesia | 6 | 35 | 51 |
| Dizziness | 10 | 8 | 9 |
| Hypoesthesia | 2 | 6 | 7 |
| Language problems | 2 | 7 | 6 |
| | |||
| Nausea | 8 | 9 | 13 |
| Diarrhea | 4 | 9 | 11 |
| Abdominal pain | 5 | 6 | 6 |
| Dyspepsia | 3 | 4 | 5 |
| Dry mouth | 2 | 2 | 3 |
| Gastroenteritis | 1 | 3 | 3 |
| | |||
| Weight loss | 1 | 6 | 9 |
| | |||
| Arthralgia | 2 | 7 | 3 |
| | |||
| Anorexia | 6 | 9 | 15 |
| Somnolence | 5 | 8 | 7 |
| Difficulty with memory | 2 | 7 | 7 |
| Insomnia | 5 | 6 | 7 |
| Difficulty with concentration/attention | 2 | 3 | 6 |
| Mood problems | 2 | 3 | 6 |
| Anxiety | 3 | 4 | 5 |
| Depression | 4 | 3 | 4 |
| Nervousness | 2 | 4 | 4 |
| Confusion | 2 | 2 | 3 |
| Psychomotor slowing | 1 | 3 | 2 |
| | |||
| Menstrual disorder | 2 | 3 | 2 |
| | |||
| Ejaculation premature | 0 | 3 | 0 |
| | |||
| Viral infection | 3 | 4 | 4 |
| | |||
| Upper respiratory tract infection | 12 | 13 | 14 |
| Sinusitis | 6 | 10 | 6 |
| Pharyngitis | 4 | 5 | 6 |
| Coughing | 2 | 2 | 4 |
| Bronchitis | 2 | 3 | 3 |
| Dyspnea | 2 | 1 | 3 |
| | |||
| Pruritis | 2 | 4 | 2 |
| | |||
| Taste perversion | 1 | 15 | 8 |
| | |||
| Urinary tract infection | 2 | 4 | 2 |
| | |||
| Blurred vision c | 2 | 4 | 2 |
| a Includes 35 adolescent patients age 12 to 15 years. b Values represent the percentage of patients reporting a given adverse reaction. Patients may have reported more than one adverse reaction during the study and can be included in more than one adverse reaction category. c Blurred vision was the most common term considered as vision abnormal. Blurred vision was an included term that accounted for >50% of reactions coded as vision abnormal, a preferred term. | |||
| Placebo (N=45)% | Topiramate Dosage | ||
| 50 mg/day (N=46) % | 100 mg/day (N=48) % | ||
| | |||
| Fatigue | 7 | 7 | 8 |
| Fever | 2 | 4 | 6 |
| | |||
| Paresthesia | 7 | 20 | 19 |
| Dizziness | 4 | 4 | 6 |
| | |||
| Abdominal pain | 9 | 7 | 15 |
| Nausea | 4 | 4 | 8 |
| | |||
| Weight loss | 2 | 7 | 4 |
| | |||
| Anorexia | 4 | 9 | 10 |
| Somnolence | 2 | 2 | 6 |
| Insomnia | 2 | 9 | 2 |
| | |||
| Infection viral | 4 | 4 | 8 |
| | |||
| Upper respiratory tract infection | 11 | 26 | 23 |
| Rhinitis | 2 | 7 | 6 |
| Sinusitis | 2 | 9 | 4 |
| Coughing | 0 | 7 | 2 |
| | |||
| Taste perversion | 2 | 2 | 6 |
| | |||
| Conjunctivitis | 4 | 7 | 4 |
| a 35 adolescent patients aged 12 to <16 years were also included in adverse reaction assessment for adults (Tables 10 and 11) b Incidence is based on the number of subjects experiencing at least 1 adverse event, not the number of events. c Included studies MIG-3006, MIGR-001, MIGR-002 and MIGR-003 | |||
Topiramate Drug Interactions
Information about and practical guidance on preventing clinically significant drug/drug and drug/food interactions that may occur in people taking the drug.7 DRUG INTERACTIONS In vitro studies indicate that topiramate does not inhibit enzyme activity for CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2D6, CYP2E1, and CYP3A4/5 isozymes. In vitro studies indicate that topiramate is a mild inhibitor of CYP2C19 and a mild inducer of CYP3A4. Drug interactions with some antiepileptic drugs, CNS depressants and oral contraceptives are described here. For other drug interactions, please refer to Clinical Pharmacology ( 12.3 ) . Summary of AED interactions with topiramate ( 7.1 ) AED Coadministered AED Concentration Topiramate Concentration Phenytoin NC or 25% increase Plasma concentration increased 25% in some patients, generally those on a twice a day dosing regimen of phenytoin. 48% decrease Carbamazepine (CBZ) NC 40% decrease CBZ epoxide Is not administered but is an active metabolite of carbamazepine. NC NE Valproic acid 11% decrease 14% decrease Phenobarbital NC NE Primidone NC NE Lamotrigine NC at TPM doses up to 400 mg/day 13% decrease NC = Less than 10% change in plasma concentration. NE = Not Evaluated Oral contraceptives: Decreased contraceptive efficacy and increased breakthrough bleeding should be considered, especially at doses greater than 200 mg/day ( 7.3 ) Metformin is contraindicated with metabolic acidosis, an effect of topiramate ( 7.4 ) Lithium levels should be monitored when coadministered with high-dose topiramate ( 7.5 ) Other carbonic anhydrase inhibitors: Monitor the patient for the appearance or worsening of metabolic acidosis ( 7.6 ) 7.1 Antiepileptic Drugs Potential interactions between topiramate and standard AEDs were assessed in controlled clinical pharmacokinetic studies in patients with epilepsy. Concomitant administration of phenytoin or carbamazepine with topiramate decreased plasma concentrations of topiramate by 48% and 40%, respectively when compared to topiramate given alone [see Clinical Pharmacology ( 12.3 )] . Concomitant administration of valproic acid and topiramate has been associated with hyperammonemia with and without encephalopathy. Concomitant administration of topiramate with valproic acid has also been associated with hypothermia (with and without hyperammonemia) in patients who have tolerated either drug alone. It may be prudent to examine blood ammonia levels in patients in whom the onset of hypothermia has been reported [see Warnings and Precautions ( 5.10 ), ( 5.12 ) and Clinical Pharmacology ( 12.3 )] . 7.2 CNS Depressants Concomitant administration of topiramate and alcohol or other CNS depressant drugs has not been evaluated in clinical studies. Because of the potential of topiramate to cause CNS depression, as well as other cognitive and/or neuropsychiatric adverse reactions, topiramate should be used with extreme caution if used in combination with alcohol and other CNS depressants. 7.3 Oral Contraceptives Exposure to ethinyl estradiol was statistically significantly decreased at doses of 200, 400, and 800 mg/day (18%, 21%, and 30%, respectively) when topiramate was given as adjunctive therapy in patients taking valproic acid. However, norethindrone exposure was not significantly affected. In another pharmacokinetic interaction study in healthy volunteers with a concomitantly administered combination oral contraceptive product containing 1 mg norethindrone (NET) plus 35 mcg ethinyl estradiol (EE), topiramate, given in the absence of other medications at doses of 50 to 200 mg/day, was not associated with statistically significant changes in mean exposure (AUC) to either component of the oral contraceptive. The possibility of decreased contraceptive efficacy and increased breakthrough bleeding should be considered in patients taking combination oral contraceptive products with topiramate. Patients taking estrogen-containing contraceptives should be asked to report any change in their bleeding patterns. Contraceptive efficacy can be decreased even in the absence of breakthrough bleeding [ see Clinical Pharmacology ( 12.3 )]. 7.4 Metformin Topiramate treatment can frequently cause metabolic acidosis, a condition for which the use of metformin is contraindicated [ see Clinical Pharmacology ( 12.3 )] . 7.5 Lithium In patients, lithium levels were unaffected during treatment with topiramate at doses of 200 mg/day; however, there was an observed increase in systemic exposure of lithium (27% for C max and 26% for AUC) following topiramate doses of up to 600 mg/day. Lithium levels should be monitored when coadministered with high-dose topiramate [see Clinical Pharmacology ( 12.3 )] . 7.6 Other Carbonic Anhydrase Inhibitors Concomitant use of topiramate, a carbonic anhydrase inhibitor, with any other carbonic anhydrase inhibitor (e.g., zonisamide, acetazolamide, or dichlorphenamide) may increase the severity of metabolic acidosis and may also increase the risk of kidney stone formation. Therefore, if topiramate is given concomitantly with another carbonic anhydrase inhibitor, the patient should be monitored for the appearance or worsening of metabolic acidosis [see Clinical Pharmacology ( 12.3 )] .
| AED Coadministered | AED Concentration | Topiramate Concentration |
|---|---|---|
| Phenytoin | NC or 25% increase | 48% decrease |
| Carbamazepine (CBZ) | NC | 40% decrease |
| CBZ epoxide | NC | NE |
| Valproic acid | 11% decrease | 14% decrease |
| Phenobarbital | NC | NE |
| Primidone | NC | NE |
| Lamotrigine | NC at TPM doses up to 400 mg/day | 13% decrease |
Clinical pharmacology
Information about the clinical pharmacology and actions of the drug in humans.12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action The precise mechanisms by which topiramate exerts its anticonvulsant effect is unknown; however, preclinical studies have revealed four properties that may contribute to topiramate's efficacy for epilepsy. Electrophysiological and biochemical evidence suggests that topiramate, at pharmacologically relevant concentrations, blocks voltage-dependent sodium channels, augments the activity of the neurotransmitter gamma-aminobutyrate at some subtypes of the GABA-A receptor, antagonizes the AMPA/kainate subtype of the glutamate receptor, and inhibits the carbonic anhydrase enzyme, particularly isozymes II and IV. 12.2 Pharmacodynamics Topiramate has anticonvulsant activity in rat and mouse maximal electroshock seizure (MES) tests. Topiramate is only weakly effective in blocking clonic seizures induced by the GABA A receptor antagonist, pentylenetetrazole. Topiramate is also effective in rodent models of epilepsy, which include tonic and absence-like seizures in the spontaneous epileptic rat (SER) and tonic and clonic seizures induced in rats by kindling of the amygdala or by global ischemia. Changes (increases and decreases) from baseline in vital signs (systolic blood pressure-SBP, diastolic blood pressure-DBP, pulse) occurred more frequently in pediatric patients (6 to 17 years) treated with various daily doses of topiramate (50 mg, 100 mg, 200 mg, 2 to 3 mg/kg) than in patients treated with placebo in controlled trials for another indication . The most notable changes were SBP < 90 mm Hg, DBP < 50 mm Hg, SBP or DBP increases or decreases ≥ 20 mm Hg, and pulse increases or decreases ≥ 30 beats per minute. These changes were often dose-related, and were most frequently associated with the greatest treatment difference at the 200 mg dose level. When a position was specified for measurement of vital signs in a trial, measurements were made in a sitting position. Systematic collection of orthostatic vital signs has not been conducted. The clinical significance of these various changes in vital signs has not been clearly established. 12.3 Pharmacokinetics Absorption of topiramate is rapid, with peak plasma concentrations occurring at approximately 2 hours following a 400 mg oral dose. The relative bioavailability of topiramate from the tablet formulation is about 80% compared to a solution. The bioavailability of topiramate is not affected by food. The pharmacokinetics of topiramate are linear with dose proportional increases in plasma concentration over the dose range studied (200 to 800 mg/day). The mean plasma elimination half-life is 21 hours after single or multiple doses. Steady-state is thus reached in about 4 days in patients with normal renal function. Topiramate is 15% to 41% bound to human plasma proteins over the blood concentration range of 0.5 to 250 mcg/mL. The fraction bound decreased as blood concentration increased. Carbamazepine and phenytoin do not alter the binding of topiramate. Sodium valproate, at 500 mcg/mL (a concentration 5 to 10 times higher than considered therapeutic for valproate) decreased the protein binding of topiramate from 23% to 13%. Topiramate does not influence the binding of sodium valproate. Metabolism and Excretion Topiramate is not extensively metabolized and is primarily eliminated unchanged in the urine (approximately 70% of an administered dose). Six metabolites have been identified in humans, none of which constitutes more than 5% of an administered dose. The metabolites are formed via hydroxylation, hydrolysis, and glucuronidation. There is evidence of renal tubular reabsorption of topiramate. In rats, given probenecid to inhibit tubular reabsorption, along with topiramate, a significant increase in renal clearance of topiramate was observed. This interaction has not been evaluated in humans. Overall, oral plasma clearance (CL/F) is approximately 20 to 30 mL/min in adults following oral administration. Specific Populations Renal Impairment The clearance of topiramate was reduced by 42% in moderately renally impaired (creatinine clearance 30 to 69 mL/min/1.73 m 2 ) and by 54% in severely renally impaired subjects (creatinine clearance <30 mL/min/1.73 m 2 ) compared to normal renal function subjects (creatinine clearance >70 mL/min/1.73 m 2 ). Since topiramate is presumed to undergo significant tubular reabsorption, it is uncertain whether this experience can be generalized to all situations of renal impairment. It is conceivable that some forms of renal disease could differentially affect glomerular filtration rate and tubular reabsorption resulting in a clearance of topiramate not predicted by creatinine clearance. In general, however, use of one-half the usual starting and maintenance dose is recommended in patients with moderate or severe renal impairment [see Dosage and Administration ( 2.4 ) and ( 2.5 ) and Warnings and Precautions ( 5.14 )] . Hemodialysis Topiramate is cleared by hemodialysis. Using a high-efficiency, counterflow, single pass-dialysate hemodialysis procedure, topiramate dialysis clearance was 120 mL/min with blood flow through the dialyzer at 400 mL/min. This high clearance (compared to 20 to 30 mL/min total oral clearance in healthy adults) will remove a clinically significant amount of topiramate from the patient over the hemodialysis treatment period. Therefore, a supplemental dose may be required [see Dosage and Administration ( 2.6 )] . Hepatic Impairment In hepatically impaired subjects, the clearance of topiramate may be decreased; the mechanism underlying the decrease is not well understood [see Dosage and Administration ( 2.7 )] . Age, Gender, and Race The pharmacokinetics of topiramate in elderly subjects (65 to 85 years of age, N=16) were evaluated in a controlled clinical study. The elderly subject population had reduced renal function (creatinine clearance [-20%]) compared to young adults. Following a single oral 100 mg dose, maximum plasma concentration for elderly and young adults was achieved at approximately 1 to 2 hours. Reflecting the primary renal elimination of topiramate, topiramate plasma and renal clearance were reduced 21% and 19%, respectively, in elderly subjects, compared to young adults. Similarly, topiramate half-life was longer (13%) in the elderly. Reduced topiramate clearance resulted in slightly higher maximum plasma concentration (23%) and AUC (25%) in elderly subjects than observed in young adults. Topiramate clearance is decreased in the elderly only to the extent that renal function is reduced. As recommended for all patients, dosage adjustment may be indicated in the elderly patient when impaired renal function (creatinine clearance rate ≤70 mL/min/1.73 m 2 ) is evident. It may be useful to monitor renal function in the elderly patient [see Dosage and Administration ( 2.4 ) and Warnings and Precautions ( 5.14 )] . Clearance of topiramate in adults was not affected by gender or race. Pediatric Pharmacokinetics Pharmacokinetics of topiramate were evaluated in patients age 2 to <16 years. Patients received either no or a combination of other antiepileptic drugs. A population pharmacokinetic model was developed on the basis of pharmacokinetic data from relevant topiramate clinical studies. This dataset contained data from 1217 subjects including 258 pediatric patients age 2 to <16 years (95 pediatric patients <10 years of age). Pediatric patients on adjunctive treatment exhibited a higher oral clearance (L/h) of topiramate compared to patients on monotherapy, presumably because of increased clearance from concomitant enzyme-inducing antiepileptic drugs. In comparison, topiramate clearance per kg is greater in pediatric patients than in adults and in young pediatric patients (down to 2 years) than in older pediatric patients. Consequently, the plasma drug concentration for the same mg/kg/day dose would be lower in pediatric patients compared to adults and also in younger pediatric patients compared to older pediatric patients. Clearance was independent of dose. As in adults, hepatic enzyme-inducing antiepileptic drugs decrease the steady state plasma concentrations of topiramate. Drug-Drug Interactions Antiepileptic Drugs Potential interactions between topiramate and standard AEDs were assessed in controlled clinical pharmacokinetic studies in patients with epilepsy. The effects of these interactions on mean plasma AUCs are summarized in Table 13. In Table 13, the second column (AED concentration) describes what happens to the concentration of the AED listed in the first column when topiramate is added. The third column (topiramate concentration) describes how the coadministration of a drug listed in the first column modifies the concentration of topiramate in experimental settings when topiramate was given alone. Table 13: Summary of AED Interactions with Topiramate AED Coadministered AED Concentration Topiramate Concentration NC = Less than 10% change in plasma concentration. AED = Antiepileptic drug. NE = Not Evaluated. TPM = Topiramate Phenytoin NC or 25% increase Plasma concentration increased 25% in some patients, generally those on a twice a day dosing regimen of phenytoin. 48% decrease Carbamazepine (CBZ) NC 40% decrease CBZ epoxide Is not administered but is an active metabolite of carbamazepine. NC NE Valproic acid 11% decrease 14% decrease Phenobarbital NC NE Primidone NC NE Lamotrigine NC at TPM doses up to 400 mg/day 13% decrease In addition to the pharmacokinetic interaction described in the above table, concomitant administration of valproic acid and topiramate has been associated with hyperammonemia with and without encephalopathy and hypothermia [see Warnings and Precautions ( 5.10 ), ( 5.12 ) and Drug Interactions ( 7.1 )] . CNS Depressants Concomitant administration of topiramate and alcohol or other CNS depressant drugs has not been evaluated in clinical studies. Because of the potential of topiramate to cause CNS depression, as well as other cognitive and/or neuropsychiatric adverse reactions, topiramate should be used with extreme caution if used in combination with alcohol and other CNS depressants [see Drug Interactions ( 7.2 )]. Oral Contraceptives In a pharmacokinetic interaction study in healthy volunteers with a concomitantly administered combination oral contraceptive product containing 1 mg norethindrone (NET) plus 35 mcg ethinyl estradiol (EE), topiramate, given in the absence of other medications at doses of 50 to 200 mg/day, was not associated with statistically significant changes in mean exposure (AUC) to either component of the oral contraceptive. In another study, exposure to EE was statistically significantly decreased at doses of 200, 400, and 800 mg/day (18%, 21%, and 30%, respectively) when given as adjunctive therapy in patients taking valproic acid. In both studies, topiramate (50 mg/day to 800 mg/day) did not significantly affect exposure to NET. Although there was a dose-dependent decrease in EE exposure for doses between 200 and 800 mg/day, there was no significant dose-dependent change in EE exposure for doses of 50 to 200 mg/day. The clinical significance of the changes observed is not known. The possibility of decreased contraceptive efficacy and increased breakthrough bleeding should be considered in patients taking combination oral contraceptive products with topiramate. Patients taking estrogen-containing contraceptives should be asked to report any change in their bleeding patterns. Contraceptive efficacy can be decreased even in the absence of breakthrough bleeding [see Drug Interactions ( 7.3 )] . Digoxin In a single-dose study, serum digoxin AUC was decreased by 12% with concomitant topiramate administration. The clinical relevance of this observation has not been established. Hydrochlorothiazide A drug-drug interaction study conducted in healthy volunteers evaluated the steady-state pharmacokinetics of hydrochlorothiazide (HCTZ) (25 mg q24h) and topiramate (96 mg q12h) when administered alone and concomitantly. The results of this study indicate that topiramate C max increased by 27% and AUC increased by 29% when HCTZ was added to topiramate. The clinical significance of this change is unknown. The addition of HCTZ to topiramate therapy may require an adjustment of the topiramate dose. The steady-state pharmacokinetics of HCTZ were not significantly influenced by the concomitant administration of topiramate. Clinical laboratory results indicated decreases in serum potassium after topiramate or HCTZ administration, which were greater when HCTZ and topiramate were administered in combination. Metformin Topiramate treatment can frequently cause metabolic acidosis, a condition for which the use of metformin is contraindicated. A drug-drug interaction study conducted in healthy volunteers evaluated the steady-state pharmacokinetics of metformin (500 mg every 12 hr) and topiramate in plasma when metformin was given alone and when metformin and topiramate (100 mg every 12 hr) were given simultaneously. The results of this study indicated that the mean metformin C max and AUC 0-12h increased by 18% and 25%, respectively, when topiramate was added. Topiramate did not affect metformin t max . The clinical significance of the effect of topiramate on metformin pharmacokinetics is not known. Oral plasma clearance of topiramate appears to be reduced when administered with metformin. The clinical significance of the effect of metformin on topiramate pharmacokinetics is unclear [see Drug Interactions ( 7.4 )] . Pioglitazone A drug-drug interaction study conducted in healthy volunteers evaluated the steady-state pharmacokinetics of topiramate and pioglitazone when administered alone and concomitantly. A 15% decrease in the AUCτ,ss of pioglitazone with no alteration in C max,ss was observed. This finding was not statistically significant. In addition, a 13% and 16% decrease in C max,ss and AUCτ ,ss respectively, of the active hydroxy-metabolite was noted as well as a 60% decrease in C max,ss and AUCτ ,ss of the active keto-metabolite. The clinical significance of these findings is not known. When topiramate is added to pioglitazone therapy or pioglitazone is added to topiramate therapy, careful attention should be given to the routine monitoring of patients for adequate control of their diabetic disease state. Glyburide A drug-drug interaction study conducted in patients with type 2 diabetes evaluated the steady-state pharmacokinetics of glyburide (5 mg/day) alone and concomitantly with topiramate (150 mg/day). There was a 22% decrease in C max and a 25% reduction in AUC 24 for glyburide during topiramate administration. Systemic exposure (AUC) of the active metabolites, 4- trans -hydroxy-glyburide (M1) and 3- cis -hydroxyglyburide (M2), was also reduced by 13% and 15%, and C max was reduced by 18% and 25%, respectively. The steady-state pharmacokinetics of topiramate were unaffected by concomitant administration of glyburide. Lithium In patients, the pharmacokinetics of lithium were unaffected during treatment with topiramate at doses of 200 mg/day; however, there was an observed increase in systemic exposure of lithium (27% for C max and 26% for AUC) following topiramate doses up to 600 mg/day. Lithium levels should be monitored when coadministered with high-dose topiramate [see Drug Interactions ( 7.5 )] . Haloperidol The pharmacokinetics of a single dose of haloperidol (5 mg) were not affected following multiple dosing of topiramate (100 mg every 12 hr) in 13 healthy adults (6 males, 7 females). Amitriptyline There was a 12% increase in AUC and C max for amitriptyline (25 mg per day) in 18 normal subjects (9 males, 9 females) receiving 200 mg/day of topiramate. Some subjects may experience a large increase in amitriptyline concentration in the presence of topiramate and any adjustments in amitriptyline dose should be made according to the patient's clinical response and not on the basis of plasma levels. Sumatriptan Multiple dosing of topiramate (100 mg every 12 hrs) in 24 healthy volunteers (14 males, 10 females) did not affect the pharmacokinetics of single-dose sumatriptan either orally (100 mg) or subcutaneously (6 mg). Risperidone When administered concomitantly with topiramate at escalating doses of 100, 250, and 400 mg/day, there was a reduction in risperidone systemic exposure (16% and 33% for steady-state AUC at the 250 and 400 mg/day doses of topiramate). No alterations of 9-hydroxyrisperidone levels were observed. Coadministration of topiramate 400 mg/day with risperidone resulted in a 14% increase in C max and a 12% increase in AUC 12 of topiramate. There were no clinically significant changes in the systemic exposure of risperidone plus 9-hydroxyrisperidone or of topiramate; therefore, this interaction is not likely to be of clinical significance. Propranolol Multiple dosing of topiramate (200 mg/day) in 34 healthy volunteers (17 males, 17 females) did not affect the pharmacokinetics of propranolol following daily 160 mg doses. Propranolol doses of 160 mg/day in 39 volunteers (27 males, 12 females) had no effect on the exposure to topiramate, at a dose of 200 mg/day of topiramate. Dihydroergotamine Multiple dosing of topiramate (200 mg/day) in 24 healthy volunteers (12 males, 12 females) did not affect the pharmacokinetics of a 1 mg subcutaneous dose of dihydroergotamine. Similarly, a 1 mg subcutaneous dose of dihydroergotamine did not affect the pharmacokinetics of a 200 mg/day dose of topiramate in the same study. Diltiazem Coadministration of diltiazem (240 mg Cardizem CD ® *) with topiramate (150 mg/day) resulted in a 10% decrease in C max and a 25% decrease in diltiazem AUC, a 27% decrease in C max and an 18% decrease in des-acetyl diltiazem AUC, and no effect on N-desmethyl diltiazem. Coadministration of topiramate with diltiazem resulted in a 16% increase in C max and a 19% increase in AUC 12 of topiramate. Venlafaxine Multiple dosing of topiramate (150 mg/day) in healthy volunteers did not affect the pharmacokinetics of venlafaxine or O-desmethyl venlafaxine. Multiple dosing of venlafaxine (150 mg Effexor XR ® *) did not affect the pharmacokinetics of topiramate. Other Carbonic Anhydrase Inhibitors Concomitant use of topiramate, a carbonic anhydrase inhibitor, with any other carbonic anhydrase inhibitor (e.g., zonisamide, acetazolamide, or dichlorphenamide) may increase the severity of metabolic acidosis and may also increase the risk of kidney stone formation. Therefore, if topiramate is given concomitantly with another carbonic anhydrase inhibitor, the patient should be monitored for the appearance or worsening of metabolic acidosis [ see Drug Interactions ( 7.6 ) ]. Drug/Laboratory Tests Interactions There are no known interactions of topiramate with commonly used laboratory tests.
| AED Coadministered | AED Concentration | Topiramate Concentration |
|---|---|---|
| NC = Less than 10% change in plasma concentration. AED = Antiepileptic drug. NE = Not Evaluated. TPM = Topiramate | ||
| Phenytoin | NC or 25% increase | 48% decrease |
| Carbamazepine (CBZ) | NC | 40% decrease |
| CBZ epoxide | NC | NE |
| Valproic acid | 11% decrease | 14% decrease |
| Phenobarbital | NC | NE |
| Primidone | NC | NE |
| Lamotrigine | NC at TPM doses up to 400 mg/day | 13% decrease |
Mechanism of action
Information about the established mechanism(s) of the drugÕs action in humans at various levels (for example receptor, membrane, tissue, organ, whole body). If the mechanism of action is not known, this field contains a statement about the lack of information.12.1 Mechanism of Action The precise mechanisms by which topiramate exerts its anticonvulsant effect is unknown; however, preclinical studies have revealed four properties that may contribute to topiramate's efficacy for epilepsy. Electrophysiological and biochemical evidence suggests that topiramate, at pharmacologically relevant concentrations, blocks voltage-dependent sodium channels, augments the activity of the neurotransmitter gamma-aminobutyrate at some subtypes of the GABA-A receptor, antagonizes the AMPA/kainate subtype of the glutamate receptor, and inhibits the carbonic anhydrase enzyme, particularly isozymes II and IV.
Pharmacodynamics
Information about any biochemical or physiologic pharmacologic effects of the drug or active metabolites related to the drugÕs clinical effect in preventing, diagnosing, mitigating, curing, or treating disease, or those related to adverse effects or toxicity.12.2 Pharmacodynamics Topiramate has anticonvulsant activity in rat and mouse maximal electroshock seizure (MES) tests. Topiramate is only weakly effective in blocking clonic seizures induced by the GABA A receptor antagonist, pentylenetetrazole. Topiramate is also effective in rodent models of epilepsy, which include tonic and absence-like seizures in the spontaneous epileptic rat (SER) and tonic and clonic seizures induced in rats by kindling of the amygdala or by global ischemia. Changes (increases and decreases) from baseline in vital signs (systolic blood pressure-SBP, diastolic blood pressure-DBP, pulse) occurred more frequently in pediatric patients (6 to 17 years) treated with various daily doses of topiramate (50 mg, 100 mg, 200 mg, 2 to 3 mg/kg) than in patients treated with placebo in controlled trials for another indication . The most notable changes were SBP < 90 mm Hg, DBP < 50 mm Hg, SBP or DBP increases or decreases ≥ 20 mm Hg, and pulse increases or decreases ≥ 30 beats per minute. These changes were often dose-related, and were most frequently associated with the greatest treatment difference at the 200 mg dose level. When a position was specified for measurement of vital signs in a trial, measurements were made in a sitting position. Systematic collection of orthostatic vital signs has not been conducted. The clinical significance of these various changes in vital signs has not been clearly established.
Pharmacokinetics
Information about the clinically significant pharmacokinetics of a drug or active metabolites, for instance pertinent absorption, distribution, metabolism, and excretion parameters.12.3 Pharmacokinetics Absorption of topiramate is rapid, with peak plasma concentrations occurring at approximately 2 hours following a 400 mg oral dose. The relative bioavailability of topiramate from the tablet formulation is about 80% compared to a solution. The bioavailability of topiramate is not affected by food. The pharmacokinetics of topiramate are linear with dose proportional increases in plasma concentration over the dose range studied (200 to 800 mg/day). The mean plasma elimination half-life is 21 hours after single or multiple doses. Steady-state is thus reached in about 4 days in patients with normal renal function. Topiramate is 15% to 41% bound to human plasma proteins over the blood concentration range of 0.5 to 250 mcg/mL. The fraction bound decreased as blood concentration increased. Carbamazepine and phenytoin do not alter the binding of topiramate. Sodium valproate, at 500 mcg/mL (a concentration 5 to 10 times higher than considered therapeutic for valproate) decreased the protein binding of topiramate from 23% to 13%. Topiramate does not influence the binding of sodium valproate. Metabolism and Excretion Topiramate is not extensively metabolized and is primarily eliminated unchanged in the urine (approximately 70% of an administered dose). Six metabolites have been identified in humans, none of which constitutes more than 5% of an administered dose. The metabolites are formed via hydroxylation, hydrolysis, and glucuronidation. There is evidence of renal tubular reabsorption of topiramate. In rats, given probenecid to inhibit tubular reabsorption, along with topiramate, a significant increase in renal clearance of topiramate was observed. This interaction has not been evaluated in humans. Overall, oral plasma clearance (CL/F) is approximately 20 to 30 mL/min in adults following oral administration. Specific Populations Renal Impairment The clearance of topiramate was reduced by 42% in moderately renally impaired (creatinine clearance 30 to 69 mL/min/1.73 m 2 ) and by 54% in severely renally impaired subjects (creatinine clearance <30 mL/min/1.73 m 2 ) compared to normal renal function subjects (creatinine clearance >70 mL/min/1.73 m 2 ). Since topiramate is presumed to undergo significant tubular reabsorption, it is uncertain whether this experience can be generalized to all situations of renal impairment. It is conceivable that some forms of renal disease could differentially affect glomerular filtration rate and tubular reabsorption resulting in a clearance of topiramate not predicted by creatinine clearance. In general, however, use of one-half the usual starting and maintenance dose is recommended in patients with moderate or severe renal impairment [see Dosage and Administration ( 2.4 ) and ( 2.5 ) and Warnings and Precautions ( 5.14 )] . Hemodialysis Topiramate is cleared by hemodialysis. Using a high-efficiency, counterflow, single pass-dialysate hemodialysis procedure, topiramate dialysis clearance was 120 mL/min with blood flow through the dialyzer at 400 mL/min. This high clearance (compared to 20 to 30 mL/min total oral clearance in healthy adults) will remove a clinically significant amount of topiramate from the patient over the hemodialysis treatment period. Therefore, a supplemental dose may be required [see Dosage and Administration ( 2.6 )] . Hepatic Impairment In hepatically impaired subjects, the clearance of topiramate may be decreased; the mechanism underlying the decrease is not well understood [see Dosage and Administration ( 2.7 )] . Age, Gender, and Race The pharmacokinetics of topiramate in elderly subjects (65 to 85 years of age, N=16) were evaluated in a controlled clinical study. The elderly subject population had reduced renal function (creatinine clearance [-20%]) compared to young adults. Following a single oral 100 mg dose, maximum plasma concentration for elderly and young adults was achieved at approximately 1 to 2 hours. Reflecting the primary renal elimination of topiramate, topiramate plasma and renal clearance were reduced 21% and 19%, respectively, in elderly subjects, compared to young adults. Similarly, topiramate half-life was longer (13%) in the elderly. Reduced topiramate clearance resulted in slightly higher maximum plasma concentration (23%) and AUC (25%) in elderly subjects than observed in young adults. Topiramate clearance is decreased in the elderly only to the extent that renal function is reduced. As recommended for all patients, dosage adjustment may be indicated in the elderly patient when impaired renal function (creatinine clearance rate ≤70 mL/min/1.73 m 2 ) is evident. It may be useful to monitor renal function in the elderly patient [see Dosage and Administration ( 2.4 ) and Warnings and Precautions ( 5.14 )] . Clearance of topiramate in adults was not affected by gender or race. Pediatric Pharmacokinetics Pharmacokinetics of topiramate were evaluated in patients age 2 to <16 years. Patients received either no or a combination of other antiepileptic drugs. A population pharmacokinetic model was developed on the basis of pharmacokinetic data from relevant topiramate clinical studies. This dataset contained data from 1217 subjects including 258 pediatric patients age 2 to <16 years (95 pediatric patients <10 years of age). Pediatric patients on adjunctive treatment exhibited a higher oral clearance (L/h) of topiramate compared to patients on monotherapy, presumably because of increased clearance from concomitant enzyme-inducing antiepileptic drugs. In comparison, topiramate clearance per kg is greater in pediatric patients than in adults and in young pediatric patients (down to 2 years) than in older pediatric patients. Consequently, the plasma drug concentration for the same mg/kg/day dose would be lower in pediatric patients compared to adults and also in younger pediatric patients compared to older pediatric patients. Clearance was independent of dose. As in adults, hepatic enzyme-inducing antiepileptic drugs decrease the steady state plasma concentrations of topiramate. Drug-Drug Interactions Antiepileptic Drugs Potential interactions between topiramate and standard AEDs were assessed in controlled clinical pharmacokinetic studies in patients with epilepsy. The effects of these interactions on mean plasma AUCs are summarized in Table 13. In Table 13, the second column (AED concentration) describes what happens to the concentration of the AED listed in the first column when topiramate is added. The third column (topiramate concentration) describes how the coadministration of a drug listed in the first column modifies the concentration of topiramate in experimental settings when topiramate was given alone. Table 13: Summary of AED Interactions with Topiramate AED Coadministered AED Concentration Topiramate Concentration NC = Less than 10% change in plasma concentration. AED = Antiepileptic drug. NE = Not Evaluated. TPM = Topiramate Phenytoin NC or 25% increase Plasma concentration increased 25% in some patients, generally those on a twice a day dosing regimen of phenytoin. 48% decrease Carbamazepine (CBZ) NC 40% decrease CBZ epoxide Is not administered but is an active metabolite of carbamazepine. NC NE Valproic acid 11% decrease 14% decrease Phenobarbital NC NE Primidone NC NE Lamotrigine NC at TPM doses up to 400 mg/day 13% decrease In addition to the pharmacokinetic interaction described in the above table, concomitant administration of valproic acid and topiramate has been associated with hyperammonemia with and without encephalopathy and hypothermia [see Warnings and Precautions ( 5.10 ), ( 5.12 ) and Drug Interactions ( 7.1 )] . CNS Depressants Concomitant administration of topiramate and alcohol or other CNS depressant drugs has not been evaluated in clinical studies. Because of the potential of topiramate to cause CNS depression, as well as other cognitive and/or neuropsychiatric adverse reactions, topiramate should be used with extreme caution if used in combination with alcohol and other CNS depressants [see Drug Interactions ( 7.2 )]. Oral Contraceptives In a pharmacokinetic interaction study in healthy volunteers with a concomitantly administered combination oral contraceptive product containing 1 mg norethindrone (NET) plus 35 mcg ethinyl estradiol (EE), topiramate, given in the absence of other medications at doses of 50 to 200 mg/day, was not associated with statistically significant changes in mean exposure (AUC) to either component of the oral contraceptive. In another study, exposure to EE was statistically significantly decreased at doses of 200, 400, and 800 mg/day (18%, 21%, and 30%, respectively) when given as adjunctive therapy in patients taking valproic acid. In both studies, topiramate (50 mg/day to 800 mg/day) did not significantly affect exposure to NET. Although there was a dose-dependent decrease in EE exposure for doses between 200 and 800 mg/day, there was no significant dose-dependent change in EE exposure for doses of 50 to 200 mg/day. The clinical significance of the changes observed is not known. The possibility of decreased contraceptive efficacy and increased breakthrough bleeding should be considered in patients taking combination oral contraceptive products with topiramate. Patients taking estrogen-containing contraceptives should be asked to report any change in their bleeding patterns. Contraceptive efficacy can be decreased even in the absence of breakthrough bleeding [see Drug Interactions ( 7.3 )] . Digoxin In a single-dose study, serum digoxin AUC was decreased by 12% with concomitant topiramate administration. The clinical relevance of this observation has not been established. Hydrochlorothiazide A drug-drug interaction study conducted in healthy volunteers evaluated the steady-state pharmacokinetics of hydrochlorothiazide (HCTZ) (25 mg q24h) and topiramate (96 mg q12h) when administered alone and concomitantly. The results of this study indicate that topiramate C max increased by 27% and AUC increased by 29% when HCTZ was added to topiramate. The clinical significance of this change is unknown. The addition of HCTZ to topiramate therapy may require an adjustment of the topiramate dose. The steady-state pharmacokinetics of HCTZ were not significantly influenced by the concomitant administration of topiramate. Clinical laboratory results indicated decreases in serum potassium after topiramate or HCTZ administration, which were greater when HCTZ and topiramate were administered in combination. Metformin Topiramate treatment can frequently cause metabolic acidosis, a condition for which the use of metformin is contraindicated. A drug-drug interaction study conducted in healthy volunteers evaluated the steady-state pharmacokinetics of metformin (500 mg every 12 hr) and topiramate in plasma when metformin was given alone and when metformin and topiramate (100 mg every 12 hr) were given simultaneously. The results of this study indicated that the mean metformin C max and AUC 0-12h increased by 18% and 25%, respectively, when topiramate was added. Topiramate did not affect metformin t max . The clinical significance of the effect of topiramate on metformin pharmacokinetics is not known. Oral plasma clearance of topiramate appears to be reduced when administered with metformin. The clinical significance of the effect of metformin on topiramate pharmacokinetics is unclear [see Drug Interactions ( 7.4 )] . Pioglitazone A drug-drug interaction study conducted in healthy volunteers evaluated the steady-state pharmacokinetics of topiramate and pioglitazone when administered alone and concomitantly. A 15% decrease in the AUCτ,ss of pioglitazone with no alteration in C max,ss was observed. This finding was not statistically significant. In addition, a 13% and 16% decrease in C max,ss and AUCτ ,ss respectively, of the active hydroxy-metabolite was noted as well as a 60% decrease in C max,ss and AUCτ ,ss of the active keto-metabolite. The clinical significance of these findings is not known. When topiramate is added to pioglitazone therapy or pioglitazone is added to topiramate therapy, careful attention should be given to the routine monitoring of patients for adequate control of their diabetic disease state. Glyburide A drug-drug interaction study conducted in patients with type 2 diabetes evaluated the steady-state pharmacokinetics of glyburide (5 mg/day) alone and concomitantly with topiramate (150 mg/day). There was a 22% decrease in C max and a 25% reduction in AUC 24 for glyburide during topiramate administration. Systemic exposure (AUC) of the active metabolites, 4- trans -hydroxy-glyburide (M1) and 3- cis -hydroxyglyburide (M2), was also reduced by 13% and 15%, and C max was reduced by 18% and 25%, respectively. The steady-state pharmacokinetics of topiramate were unaffected by concomitant administration of glyburide. Lithium In patients, the pharmacokinetics of lithium were unaffected during treatment with topiramate at doses of 200 mg/day; however, there was an observed increase in systemic exposure of lithium (27% for C max and 26% for AUC) following topiramate doses up to 600 mg/day. Lithium levels should be monitored when coadministered with high-dose topiramate [see Drug Interactions ( 7.5 )] . Haloperidol The pharmacokinetics of a single dose of haloperidol (5 mg) were not affected following multiple dosing of topiramate (100 mg every 12 hr) in 13 healthy adults (6 males, 7 females). Amitriptyline There was a 12% increase in AUC and C max for amitriptyline (25 mg per day) in 18 normal subjects (9 males, 9 females) receiving 200 mg/day of topiramate. Some subjects may experience a large increase in amitriptyline concentration in the presence of topiramate and any adjustments in amitriptyline dose should be made according to the patient's clinical response and not on the basis of plasma levels. Sumatriptan Multiple dosing of topiramate (100 mg every 12 hrs) in 24 healthy volunteers (14 males, 10 females) did not affect the pharmacokinetics of single-dose sumatriptan either orally (100 mg) or subcutaneously (6 mg). Risperidone When administered concomitantly with topiramate at escalating doses of 100, 250, and 400 mg/day, there was a reduction in risperidone systemic exposure (16% and 33% for steady-state AUC at the 250 and 400 mg/day doses of topiramate). No alterations of 9-hydroxyrisperidone levels were observed. Coadministration of topiramate 400 mg/day with risperidone resulted in a 14% increase in C max and a 12% increase in AUC 12 of topiramate. There were no clinically significant changes in the systemic exposure of risperidone plus 9-hydroxyrisperidone or of topiramate; therefore, this interaction is not likely to be of clinical significance. Propranolol Multiple dosing of topiramate (200 mg/day) in 34 healthy volunteers (17 males, 17 females) did not affect the pharmacokinetics of propranolol following daily 160 mg doses. Propranolol doses of 160 mg/day in 39 volunteers (27 males, 12 females) had no effect on the exposure to topiramate, at a dose of 200 mg/day of topiramate. Dihydroergotamine Multiple dosing of topiramate (200 mg/day) in 24 healthy volunteers (12 males, 12 females) did not affect the pharmacokinetics of a 1 mg subcutaneous dose of dihydroergotamine. Similarly, a 1 mg subcutaneous dose of dihydroergotamine did not affect the pharmacokinetics of a 200 mg/day dose of topiramate in the same study. Diltiazem Coadministration of diltiazem (240 mg Cardizem CD ® *) with topiramate (150 mg/day) resulted in a 10% decrease in C max and a 25% decrease in diltiazem AUC, a 27% decrease in C max and an 18% decrease in des-acetyl diltiazem AUC, and no effect on N-desmethyl diltiazem. Coadministration of topiramate with diltiazem resulted in a 16% increase in C max and a 19% increase in AUC 12 of topiramate. Venlafaxine Multiple dosing of topiramate (150 mg/day) in healthy volunteers did not affect the pharmacokinetics of venlafaxine or O-desmethyl venlafaxine. Multiple dosing of venlafaxine (150 mg Effexor XR ® *) did not affect the pharmacokinetics of topiramate. Other Carbonic Anhydrase Inhibitors Concomitant use of topiramate, a carbonic anhydrase inhibitor, with any other carbonic anhydrase inhibitor (e.g., zonisamide, acetazolamide, or dichlorphenamide) may increase the severity of metabolic acidosis and may also increase the risk of kidney stone formation. Therefore, if topiramate is given concomitantly with another carbonic anhydrase inhibitor, the patient should be monitored for the appearance or worsening of metabolic acidosis [ see Drug Interactions ( 7.6 ) ]. Drug/Laboratory Tests Interactions There are no known interactions of topiramate with commonly used laboratory tests.
| AED Coadministered | AED Concentration | Topiramate Concentration |
|---|---|---|
| NC = Less than 10% change in plasma concentration. AED = Antiepileptic drug. NE = Not Evaluated. TPM = Topiramate | ||
| Phenytoin | NC or 25% increase | 48% decrease |
| Carbamazepine (CBZ) | NC | 40% decrease |
| CBZ epoxide | NC | NE |
| Valproic acid | 11% decrease | 14% decrease |
| Phenobarbital | NC | NE |
| Primidone | NC | NE |
| Lamotrigine | NC at TPM doses up to 400 mg/day | 13% decrease |
Contraindications
Information about situations in which the drug product is contraindicated or should not be used because the risk of use clearly outweighs any possible benefit, including the type and nature of reactions that have been reported.4 CONTRAINDICATIONS None. None (4)
Description
General information about the drug product, including the proprietary and established name of the drug, the type of dosage form and route of administration to which the label applies, qualitative and quantitative ingredient information, the pharmacologic or therapeutic class of the drug, and the chemical name and structural formula of the drug.11 DESCRIPTION Topiramate is a sulfamate-substituted monosaccharide. Topiramate tablets are available as 25 mg, 50 mg, 100 mg, and 200 mg round tablets for oral administration. Topiramate is a white crystalline powder with a bitter taste. Topiramate USP is most soluble in alkaline solutions containing sodium hydroxide or sodium phosphate and having a pH of 9 to 10. It is freely soluble in acetone, chloroform, dimethylsulfoxide, and ethanol. The solubility in water is 9.8 mg/mL. Its saturated solution has a pH of 6.3. Topiramate has the molecular formula C 12 H 21 NO 8 S and a molecular weight of 339.37. Topiramate is designated chemically as 2,3:4,5-Di- O -isopropylidene-β-D-fructopyranose sulfamate and has the following structural formula: Topiramate tablets, USP contain the following inactive ingredients: anhydrous lactose, microcrystalline cellulose, pregelatinized maize starch, sodium starch glycolate type A potato, magnesium stearate, polyvinyl alcohol, titanium dioxide, polyethylene glycol and talc. In addition, individual tablets contain: 50 mg tablets: iron oxide yellow 100 mg tablets: iron oxide yellow, and D&C Yellow # 10 Aluminum Lake 200 mg tablets: iron oxide red, lecithin (soya), and iron oxide black chemical-structure
Dosage and administration
Information about the drug product’s dosage and administration recommendations, including starting dose, dose range, titration regimens, and any other clinically sigificant information that affects dosing recommendations.2 DOSAGE AND ADMINISTRATION See DOSAGE AND ADMINISTRATION, Epilepsy: Monotherapy and Adjunctive Therapy Use for additional details ( 2.1 ) Initial Dose Titration Recommended Dose Epilepsy monotherapy: children 2 to <10 years ( 2.1 ) 25 mg/day administered nightly for the first week The dosage should be titrated over 5 to 7 weeks Daily doses in two divided doses based on weight (Table 2) Epilepsy monotherapy: adults and pediatric patients ≥10 years ( 2.1 ) 50 mg/day in two divided doses The dosage should be increased weekly by increments of 50 mg for the first 4 weeks then 100 mg for weeks 5 to 6. 400 mg/day in two divided doses Epilepsy adjunctive therapy: adults with partial onset seizures or LGS ( 2.1 ) 25 to 50 mg/day The dosage should be increased weekly to an effective dose by increments of 25 to 50 mg. 200 to 400 mg/day in two divided doses Epilepsy adjunctive therapy: adults with primary generalized tonic clonic seizures ( 2.1 ) 25 to 50 mg/day The dosage should be increased weekly to an effective dose by increments of 25 to 50 mg. 400 mg/day in two divided doses Epilepsy adjunctive therapy: pediatric patients with partial onset seizures, primary generalized tonic-clonic seizures or LGS ( 2.1 ) 25 mg/day (or less, based on a range of 1 to 3 mg/kg/day) nightly for the first week The dosage should be increased at 1- or 2-week intervals by increments of 1 to 3 mg/kg/day (administered in two divided doses). Dose titration should be guided by clinical outcome. 5 to 9 mg/kg/day in two divided doses 2.1 Epilepsy It is not necessary to monitor topiramate plasma concentrations to optimize topiramate therapy. On occasion, the addition of topiramate tablets to phenytoin may require an adjustment of the dose of phenytoin to achieve optimal clinical outcome. Addition or withdrawal of phenytoin and/or carbamazepine during adjunctive therapy with topiramate tablets may require adjustment of the dose of topiramate tablets. Because of the bitter taste, tablets should not be broken. Topiramate tablets can be taken without regard to meals. Monotherapy Use Adults and Pediatric Patients 10 Years and Older The recommended dose for topiramate tablets monotherapy in adults and pediatric patients 10 years of age and older is 400 mg/day in two divided doses. Approximately 58% of patients randomized to 400 mg/day achieved this maximal dose in the monotherapy controlled trial; the mean dose achieved in the trial was 275 mg/day. The dose should be achieved by titration according to the following schedule (Table 1): Table 1: Monotherapy Titration Schedule for Adults and Pediatric Patients 10 years and older Morning Dose Evening Dose Week 1 25 mg 25 mg Week 2 50 mg 50 mg Week 3 75 mg 75 mg Week 4 100 mg 100 mg Week 5 150 mg 150 mg Week 6 200 mg 200 mg Children Ages 2 to <10 Years Dosing of topiramate as initial monotherapy in children 2 to < 10 years of age with partial onset or primary generalized tonic-clonic seizures was based on a pharmacometric bridging approach [see Clinical Studies ( 14.1 )] . Dosing in patients 2 to <10 years is based on weight. During the titration period, the initial dose of topiramate tablets should be 25 mg/day administered nightly for the first week. Based upon tolerability, the dosage can be increased to 50 mg/day (25 mg twice daily) in the second week. Dosage can be increased by 25 to 50 mg/day each subsequent week as tolerated. Titration to the minimum maintenance dose should be attempted over 5 to 7 weeks of the total titration period. Based upon tolerability and clinical response, additional titration to a higher dose (up to the maximum maintenance dose) can be attempted at 25 to 50 mg/day weekly increments. The total daily dose should not exceed the maximum maintenance dose for each range of body weight (Table 2). Table 2: Monotherapy Target Total Daily Maintenance Dosing for Patients 2 to <10 Years Weight (kg) Total Daily Dose (mg/day) Administered in two equally divided doses Minimum Maintenance Dose Total Daily Dose (mg/day) Maximum Maintenance Dose Up to 11 150 250 12 to 22 200 300 23 to 31 200 350 32 to 38 250 350 Greater than 38 250 400 Adjunctive Therapy Use Adults 17 Years of Age and Over - Partial Onset Seizures, Primary Generalized Tonic-Clonic Seizures, or Lennox-Gastaut Syndrome The recommended total daily dose of topiramate tablets as adjunctive therapy in adults with partial onset seizures is 200 to 400 mg/day in two divided doses, and 400 mg/day in two divided doses as adjunctive treatment in adults with primary generalized tonic-clonic seizures. It is recommended that therapy be initiated at 25 to 50 mg/day followed by titration to an effective dose in increments of 25 to 50 mg/day every week. Titrating in increments of 25 mg/day every week may delay the time to reach an effective dose. Doses above 400 mg/day (600, 800 or 1,000 mg/day) have not been shown to improve responses in dose-response studies in adults with partial onset seizures. Daily doses above 1,600 mg have not been studied. In the study of primary generalized tonic-clonic seizures, the initial titration rate was slower than in previous studies; the assigned dose was reached at the end of 8 weeks [see Clinical Studies ( 14.1 )] . Pediatric Patients Ages 2 to 16 Years – Partial Onset Seizures, Primary Generalized Tonic-Clonic Seizures, or Lennox-Gastaut Syndrome The recommended total daily dose of topiramate tablets as adjunctive therapy for pediatric patients with partial onset seizures, primary generalized tonic-clonic seizures, or seizures associated with Lennox-Gastaut syndrome is approximately 5 to 9 mg/kg/day in two divided doses. Titration should begin at 25 mg/day (or less, based on a range of 1 to 3 mg/kg/day) nightly for the first week. The dosage should then be increased at 1- or 2-week intervals by increments of 1 to 3 mg/kg/day (administered in two divided doses), to achieve optimal clinical response. Dose titration should be guided by clinical outcome. In the study of primary generalized tonic-clonic seizures, the initial titration rate was slower than in previous studies; the assigned dose of 6 mg/kg/day was reached at the end of 8 weeks [see Clinical Studies ( 14.1 )] . Additional pediatric use information for patients ages 12 to 17 years is approved for Janssen Pharmaceuticals, Inc.’s TOPAMAX (topiramate) Tablets and Sprinkle Capsules. However, due to Janssen Pharmaceuticals, Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information. 2.4 Patients with Renal Impairment In renally impaired subjects (creatinine clearance less than 70 mL/min/1.73 m 2 ), one-half of the usual adult dose is recommended. Such patients will require a longer time to reach steady-state at each dose. 2.5 Geriatric Patients (Ages 65 Years and Over) Dosage adjustment may be indicated in the elderly patient when impaired renal function (creatinine clearance rate <70 mL/min/1.73 m 2 ) is evident [see Clinical Pharmacology ( 12.3 )] . 2.6 Patients Undergoing Hemodialysis Topiramate is cleared by hemodialysis at a rate that is 4 to 6 times greater than a normal individual. Accordingly, a prolonged period of dialysis may cause topiramate concentration to fall below that required to maintain an anti-seizure effect. To avoid rapid drops in topiramate plasma concentration during hemodialysis, a supplemental dose of topiramate may be required. The actual adjustment should take into account 1) the duration of dialysis period, 2) the clearance rate of the dialysis system being used, and 3) the effective renal clearance of topiramate in the patient being dialyzed. 2.7 Patients with Hepatic Disease In hepatically impaired patients, topiramate plasma concentrations may be increased. The mechanism is not well understood.
| Initial Dose | Titration | Recommended Dose | |
|---|---|---|---|
| Epilepsy monotherapy: children 2 to <10 years ( | 25 mg/day administered nightly for the first week | The dosage should be titrated over 5 to 7 weeks | Daily doses in two divided doses based on weight (Table 2) |
| Epilepsy monotherapy: adults and pediatric patients ≥10 years ( | 50 mg/day in two divided doses | The dosage should be increased weekly by increments of 50 mg for the first 4 weeks then 100 mg for weeks 5 to 6. | 400 mg/day in two divided doses |
| Epilepsy adjunctive therapy: adults with partial onset seizures or LGS ( | 25 to 50 mg/day | The dosage should be increased weekly to an effective dose by increments of 25 to 50 mg. | 200 to 400 mg/day in two divided doses |
| Epilepsy adjunctive therapy: adults with primary generalized tonic clonic seizures ( | 25 to 50 mg/day | The dosage should be increased weekly to an effective dose by increments of 25 to 50 mg. | 400 mg/day in two divided doses |
| Epilepsy adjunctive therapy: pediatric patients with partial onset seizures, primary generalized tonic-clonic seizures or LGS ( | 25 mg/day (or less, based on a range of 1 to 3 mg/kg/day) nightly for the first week | The dosage should be increased at 1- or 2-week intervals by increments of 1 to 3 mg/kg/day (administered in two divided doses). Dose titration should be guided by clinical outcome. | 5 to 9 mg/kg/day in two divided doses |
| Morning Dose | Evening Dose | |
|---|---|---|
| Week 1 | 25 mg | 25 mg |
| Week 2 | 50 mg | 50 mg |
| Week 3 | 75 mg | 75 mg |
| Week 4 | 100 mg | 100 mg |
| Week 5 | 150 mg | 150 mg |
| Week 6 | 200 mg | 200 mg |
| Weight (kg) | Total Daily Dose (mg/day) | Total Daily Dose (mg/day) |
|---|---|---|
| Up to 11 | 150 | 250 |
| 12 to 22 | 200 | 300 |
| 23 to 31 | 200 | 350 |
| 32 to 38 | 250 | 350 |
| Greater than 38 | 250 | 400 |
Dosage forms and strengths
Information about all available dosage forms and strengths for the drug product to which the labeling applies. This field may contain descriptions of product appearance.3 DOSAGE FORMS AND STRENGTHS Topiramate tablets, USP are available as debossed, film-coated, circular tablets in the following strengths and colors: 25 mg white (coded "S" on one side; "707" on the other) 50 mg yellow (coded "S" on one side; "710" on the other) 100 mg yellow (coded "S" on one side; "711" on the other) 200 mg brown (coded "S" on one side; "712" on the other) Tablets: 25 mg, 50 mg, 100 mg, and 200 mg ( 3 )
Indications and usage
A statement of each of the drug products indications for use, such as for the treatment, prevention, mitigation, cure, or diagnosis of a disease or condition, or of a manifestation of a recognized disease or condition, or for the relief of symptoms associated with a recognized disease or condition. This field may also describe any relevant limitations of use.1 INDICATIONS AND USAGE Topiramate is indicated for: Monotherapy epilepsy: Initial monotherapy in patients ≥ 2 years of age with partial onset or primary generalized tonic-clonic seizures ( 1.1 ) Adjunctive therapy epilepsy: Adjunctive therapy for adults and pediatric patients (2 to 16 years of age) with partial onset seizures or primary generalized tonic-clonic seizures, and in patients ≥2 years of age with seizures associated with Lennox-Gastaut syndrome (LGS) ( 1.2 ) 1.1 Monotherapy Epilepsy Topiramate tablets, USP are indicated as initial monotherapy in patients 2 years of age and older with partial onset or primary generalized tonic-clonic seizures. Safety and effectiveness in patients who were converted to monotherapy from a previous regimen of other anticonvulsant drugs have not been established in controlled trials [see Clinical Studies ( 14.1 )] . 1.2 Adjunctive Therapy Epilepsy Topiramate tablets, USP are indicated as adjunctive therapy for adults and pediatric patients ages 2 to 16 years with partial onset seizures or primary generalized tonic-clonic seizures, and in patients 2 years of age and older with seizures associated with Lennox-Gastaut syndrome [see Clinical Studies ( 14.2 )] . Additional pediatric use information for patients ages 12 to 17 years is approved for Janssen Pharmaceuticals, Inc.’s TOPAMAX (topiramate) Tablets and Sprinkle Capsules. However, due to Janssen Pharmaceuticals, Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information.
Spl product data elements
Usually a list of ingredients in a drug product.Topiramate Topiramate ANHYDROUS LACTOSE CELLULOSE, MICROCRYSTALLINE STARCH, CORN SODIUM STARCH GLYCOLATE TYPE A POTATO MAGNESIUM STEARATE POLYVINYL ALCOHOL TITANIUM DIOXIDE POLYETHYLENE GLYCOL, UNSPECIFIED TALC TOPIRAMATE TOPIRAMATE circular S;707
Carcinogenesis and mutagenesis and impairment of fertility
Information about carcinogenic, mutagenic, or fertility impairment potential revealed by studies in animals. Information from human data about such potential is part of the warnings field.13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenesis An increase in urinary bladder tumors was observed in mice given topiramate (20, 75, and 300 mg/kg) in the diet for 21 months. The elevated bladder tumor incidence, which was statistically significant in males and females receiving 300 mg/kg, was primarily due to the increased occurrence of a smooth muscle tumor considered histomorphologically unique to mice. Plasma exposures in mice receiving 300 mg/kg were approximately 0.5 to 1 times steady-state exposures measured in patients receiving topiramate monotherapy at the recommended human dose (RHD) of 400 mg, and 1.5 to 2 times steady-state topiramate exposures in patients receiving 400 mg of topiramate plus phenytoin. The relevance of this finding to human carcinogenic risk is uncertain. No evidence of carcinogenicity was seen in rats following oral administration of topiramate for 2 years at doses up to 120 mg/kg (approximately 3 times the RHD on a mg/m 2 basis). Mutagenesis Topiramate did not demonstrate genotoxic potential when tested in a battery of in vitro and in vivo assays. Topiramate was not mutagenic in the Ames test or the in vitro mouse lymphoma assay; it did not increase unscheduled DNA synthesis in rat hepatocytes in vitro ; and it did not increase chromosomal aberrations in human lymphocytes in vitro or in rat bone marrow in vivo . Impairment of Fertility No adverse effects on male or female fertility were observed in rats at doses up to 100 mg/kg (2.5 times the RHD on a mg/m 2 basis).
Nonclinical toxicology
Information about toxicology in non-human subjects.13 NON-CLINICAL TOXICOLOGY 13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenesis An increase in urinary bladder tumors was observed in mice given topiramate (20, 75, and 300 mg/kg) in the diet for 21 months. The elevated bladder tumor incidence, which was statistically significant in males and females receiving 300 mg/kg, was primarily due to the increased occurrence of a smooth muscle tumor considered histomorphologically unique to mice. Plasma exposures in mice receiving 300 mg/kg were approximately 0.5 to 1 times steady-state exposures measured in patients receiving topiramate monotherapy at the recommended human dose (RHD) of 400 mg, and 1.5 to 2 times steady-state topiramate exposures in patients receiving 400 mg of topiramate plus phenytoin. The relevance of this finding to human carcinogenic risk is uncertain. No evidence of carcinogenicity was seen in rats following oral administration of topiramate for 2 years at doses up to 120 mg/kg (approximately 3 times the RHD on a mg/m 2 basis). Mutagenesis Topiramate did not demonstrate genotoxic potential when tested in a battery of in vitro and in vivo assays. Topiramate was not mutagenic in the Ames test or the in vitro mouse lymphoma assay; it did not increase unscheduled DNA synthesis in rat hepatocytes in vitro ; and it did not increase chromosomal aberrations in human lymphocytes in vitro or in rat bone marrow in vivo . Impairment of Fertility No adverse effects on male or female fertility were observed in rats at doses up to 100 mg/kg (2.5 times the RHD on a mg/m 2 basis).
Package label principal display panel
The content of the principal display panel of the product package, usually including the product’s name, dosage forms, and other key information about the drug product.PRINCIPAL DISPLAY PANEL-25 mg PDP
Recent major changes
A list of the section(s) that contain substantive changes that have been approved by FDA in the product labeling. The headings and subheadings, if appropriate, affected by the change are listed together with each section’s identifying number and the month and year on which the change was incorporated in the labeling.Warnings and Precautions, Visual Field Defects ( 5.2 ) 01/2014
Topiramate: Information for patients
Information necessary for patients to use the drug safely and effectively, such as precautions concerning driving or the concomitant use of other substances that may have harmful additive effects.17 PATIENT COUNSELING INFORMATION Advise the patient to read the FDA-approved patient labeling ( Medication Guide ). Eye Disorders Instruct patients taking topiramate tablets to seek immediate medical attention if they experience blurred vision, visual disturbances, or periorbital pain [see Warnings and Precautions ( 5.1 ), ( 5.2 )] . Oligohidrosis and Hyperthermia Closely monitor topiramate-treated patients, especially pediatric patients, for evidence of decreased sweating and increased body temperature, especially in hot weather. Counsel patients to contact their healthcare professionals immediately if they develop a high or persistent fever, or decreased sweating [see Warnings and Precautions ( 5.3 )] . Metabolic Acidosis Warn patients about the potential significant risk for metabolic acidosis that may be asymptomatic and may be associated with adverse effects on kidneys (e.g., kidney stones, nephrocalcinosis), bones (e.g., osteoporosis, osteomalacia, and/or rickets in children), and growth (e.g., growth delay/retardation) in pediatric patients, and on the fetus [see Warnings and Precautions ( 5.4 ) and Use in Specific Populations ( 8.1 )] . Suicidal Behavior and Ideation Counsel patients, their caregivers, and families that AEDs, including topiramate tablets, may increase the risk of suicidal thoughts and behavior, and advise of the need to be alert for the emergence or worsening of the signs and symptoms of depression, any unusual changes in mood or behavior or the emergence of suicidal thoughts, or behavior or thoughts about self-harm. Instruct patients to immediately report behaviors of concern to their healthcare providers [see Warnings and Precautions ( 5.5 )] . Interference with Cognitive and Motor Performance Warn patients about the potential for somnolence, dizziness, confusion, difficulty concentrating, or visual effects, and advise patients not to drive or operate machinery until they have gained sufficient experience on topiramate tablets to gauge whether it adversely affects their mental performance, motor performance, and/or vision [see Warnings and Precautions ( 5.6 )] . Even when taking topiramate tablets or other anticonvulsants, some patients with epilepsy will continue to have unpredictable seizures. Therefore, advise all patients taking topiramate tablets for epilepsy to exercise appropriate caution when engaging in any activities where loss of consciousness could result in serious danger to themselves or those around them (including swimming, driving a car, climbing in high places, etc.). Some patients with refractory epilepsy will need to avoid such activities altogether. Discuss the appropriate level of caution with patients, before patients with epilepsy engage in such activities. Fetal Toxicity Inform pregnant women and women of childbearing potential that use of topiramate tablets during pregnancy can cause fetal harm, including an increased risk for cleft lip and/or cleft palate (oral clefts), which occur early in pregnancy before many women know they are pregnant. There may also be risks to the fetus from chronic metabolic acidosis with use of topiramate tablets during pregnancy [see Warnings and Precautions ( 5.7 ) and Use in Specific Populations ( 8.1 ), ( 8.9 )]. When appropriate, counsel pregnant women and women of childbearing potential about alternative therapeutic options. This is particularly important when topiramate tablets use is considered for a condition not usually associated with permanent injury or death. Advise women of childbearing potential who are not planning a pregnancy to use effective contraception while using topiramate tablets, keeping in mind that there is a potential for decreased contraceptive efficacy when using estrogen-containing birth control with topiramate [see Drug Interactions ( 7.3 )] . Encourage pregnant women using topiramate tablets, to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry. The registry is collecting information about the safety of antiepileptic drugs during pregnancy. To enroll, patients can call the toll-free number, 1-888-233-2334. Information about the North American Drug Pregnancy Registry can be found at http://www.massgeneral.org/aed/ [see Use in Specific Populations ( 8.1 )] . Hyperammonemia and Encephalopathy Warn patients about the possible development of hyperammonemia with or without encephalopathy. Although hyperammonemia may be asymptomatic, clinical symptoms of hyperammonemic encephalopathy often include acute alterations in level of consciousness and/or cognitive function with lethargy or vomiting. This hyperammonemia and encephalopathy can develop with topiramate tablets treatment alone or with topiramate tablets treatment with concomitant valproic acid (VPA). Instruct patients to contact their physician if they develop unexplained lethargy, vomiting, or changes in mental status [see Warnings and Precautions ( 5.10 )]. Kidney Stones Instruct patients, particularly those with predisposing factors, to maintain an adequate fluid intake in order to minimize the risk of kidney stone formatio n [see Warnings and Precautions ( 5.11 )]. Instructions for a Missing Dose Instruct patients that if they miss a single dose of topiramate it should be taken as soon as possible. However, if a patient is within 6 hours of taking the next scheduled dose, tell the patient to wait until then to take the usual dose of topiramate, and to skip the missed dose. Tell patients that they should not take a double dose in the event of a missed dose. Advise patients to contact their healthcare provider if they have missed more than one dose.
Spl medguide
Information about the patient medication guide that accompanies the drug product. Certain drugs must be dispensed with an accompanying medication guide. This field may contain information about when to consult the medication guide and the contents of the medication guide.MEDICATION GUIDE Topiramate Tablets, USP (toe-PEER-uh-mate) Read this Medication Guide before you start taking topiramate tablets and each time you get a refill. There may be new information. This information does not take the place of talking to your healthcare provider about your medical condition or treatment. If you have any questions about topiramate tablets, talk to your healthcare provider or pharmacist. What is the most important information I should know about topiramate tablets? Topiramate tablets may cause eye problems. Serious eye problems include: any sudden decrease in vision with or without eye pain and redness, a blockage of fluid in the eye causing increased pressure in the eye (secondary angle closure glaucoma). These eye problems can lead to permanent loss of vision if not treated. You should call your healthcare provider right away if you have any new eye symptoms, including any new problems with your vision. Topiramate tablets may cause decreased sweating and increased body temperature (fever). People, especially children, should be watched for signs of decreased sweating and fever, especially in hot temperatures. Some people may need to be hospitalized for this condition. Call your healthcare provider right away if you have a high fever, a fever that does not go away, or decreased sweating. Topiramate tablets can increase the level of acid in your blood (metabolic acidosis). If left untreated, metabolic acidosis can cause brittle or soft bones (osteoporosis, osteomalacia, osteopenia), kidney stones, can slow the rate of growth in children, and may possibly harm your baby if you are pregnant. Metabolic acidosis can happen with or without symptoms. Sometimes people with metabolic acidosis will: feel tired not feel hungry (loss of appetite) feel changes in heartbeat have trouble thinking clearly Your healthcare provider should do a blood test to measure the level of acid in your blood before and during your treatment with topiramate tablets. If you are pregnant, you should talk to your healthcare provider about whether you have metabolic acidosis. Like other antiepileptic drugs, topiramate tablets may cause suicidal thoughts or actions in a very small number of people, about 1 in 500. Call a healthcare provider right away if you have any of these symptoms, especially if they are new, worse, or worry you: thoughts about suicide or dying attempts to commit suicide new or worse depression new or worse anxiety feeling agitated or restless panic attacks trouble sleeping (insomnia) new or worse irritability acting aggressive, being angry, or violent acting on dangerous impulses an extreme increase in activity and talking (mania) other unusual changes in behavior or mood Do not stop topiramate tablets without first talking to a healthcare provider. Stopping topiramate tablets suddenly can cause serious problems. Suicidal thoughts or actions can be caused by things other than medicines. If you have suicidal thoughts or actions, your healthcare provider may check for other causes. How can I watch for early symptoms of suicidal thoughts and actions? Pay attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings. Keep all follow-up visits with your healthcare provider as scheduled. Call your healthcare provider between visits as needed, especially if you are worried about symptoms. Topiramate tablets can harm your unborn baby. If you take topiramate tablets during pregnancy, your baby has a higher risk for birth defects called cleft lip and cleft palate. These defects can begin early in pregnancy, even before you know you are pregnant. Cleft lip and cleft palate may happen even in children born to women who are not taking any medicines and do not have other risk factors. There may be other medicines to treat your condition that have a lower chance of birth defects. All women of childbearing age should talk to their healthcare providers about using other possible treatments instead of topiramate tablets . If the decision is made to use topiramate tablets , you should use effective birth control (contraception) unless you are planning to become pregnant. You should talk to your doctor about the best kind of birth control to use while you are taking topiramate tablets . Tell your healthcare provider right away if you become pregnant while taking topiramate tablets . You and your healthcare provider should decide if you will continue to take topiramate tablets while you are pregnant. Metabolic acidosis may have harmful effects on your baby. Talk to your healthcare provider if topiramate tablets have caused metabolic acidosis during your pregnancy. Pregnancy Registry: If you become pregnant while taking topiramate tablets , talk to your healthcare provider about registering with the North American Antiepileptic Drug Pregnancy Registry. You can enroll in this registry by calling 1-888-233-2334. The purpose of this registry is to collect information about the safety of antiepileptic drugs during pregnancy. What are topiramate tablets? Topiramate tablets are prescription medicine used: to treat certain types of seizures (partial onset seizures and primary generalized tonic-clonic seizures) in adults and children 2 years and older, with other medicines to treat certain types of seizures (partial onset seizures, primary generalized tonic-clonic seizures, and seizures associated with Lennox-Gastaut syndrome) in adults and children 2 years and older, What should I tell my healthcare provider before taking topiramate tablets? Before taking topiramate tablets, tell your healthcare provider about all your medical conditions, including if you: have or have had depression, mood problems, or suicidal thoughts or behavior have kidney problems, have kidney stones, or are getting kidney dialysis have a history of metabolic acidosis (too much acid in the blood) have liver problems have weak, brittle, or soft bones (osteomalacia, osteoporosis, osteopenia, or decreased bone density) have lung or breathing problems have eye problems, especially glaucoma have diarrhea have a growth problem are on a diet high in fat and low in carbohydrates, which is called a ketogenic diet are having surgery are pregnant or plan to become pregnant are breastfeeding. Topiramate passes into breast milk. It is not known if the topiramate that passes into breast milk can harm your baby. Talk to your healthcare provider about the best way to feed your baby if you take topiramate tablets . Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Topiramate tablets and other medicines may affect each other causing side effects. Especially tell your healthcare provider if you take: Valproic acid any medicines that impair or decrease your thinking, concentration, or muscle coordination birth control pills. Topiramate tablets may make your birth control pills less effective. Tell your healthcare provider if your menstrual bleeding changes while you are taking birth control pills and topiramate tablets . Ask your healthcare provider if you are not sure if your medicine is listed above. Know the medicines you take. Keep a list of them to show your healthcare provider and pharmacist each time you get a new medicine. Do not start a new medicine without talking with your healthcare provider. How should I take topiramate tablets? Take topiramate tablets exactly as prescribed. Your healthcare provider may change your dose. Do not change your dose without talking to your healthcare provider. Topiramate tablets should be swallowed whole. Do not chew the tablets. They may leave a bitter taste. Topiramate tablets can be taken before, during, or after a meal. Drink plenty of fluids during the day. This may help prevent kidney stones while taking topiramate tablets . If you take too many topiramate tablets , call your healthcare provider or poison control center right away or go to the nearest emergency room. If you miss a single dose of topiramate tablets , take it as soon as you can. However, if you are within 6 hours of taking your next scheduled dose, wait until then to take your usual dose of topiramate tablets , and skip the missed dose. Do not double your dose. If you have missed more than one dose, you should call your healthcare provider for advice. Do not stop taking topiramate tablets without talking to your healthcare provider. Stopping topiramate tablets suddenly may cause serious problems. If you have epilepsy and you stop taking topiramate tablets suddenly, you may have seizures that do not stop. Your healthcare provider will tell you how to stop taking topiramate tablets slowly. Your healthcare provider may do blood tests while you take topiramate tablets . What should I avoid while taking topiramate tablets? Do not drink alcohol while taking topiramate tablets . Topiramate tablets and alcohol can affect each other causing side effects such as sleepiness and dizziness. Do not drive a car or operate heavy machinery until you know how topiramate tablets affect you. Topiramate tablets can slow your thinking and motor skills, and may affect vision. What are the possible side effects of topiramate tablets? Topiramate tablets may cause serious side effects including: See “What is the most important information I should know about topiramate tablets?” High blood ammonia levels. High ammonia in the blood can affect your mental activities, slow your alertness, make you feel tired, or cause vomiting. This has happened when topiramate tablets are taken with a medicine called valproic acid. Kidney stones. Drink plenty of fluids when taking topiramate tablets to decrease your chances of getting kidney stones. Low body temperature. Taking topiramate tablets when you are also taking valproic acid can cause a drop in body temperature to less than 95 º F, feeling tired, confusion, or coma. Effects on thinking and alertness. Topiramate tablets may affect how you think and cause confusion, problems with concentration, attention, memory, or speech. Topiramate tablets may cause depression or mood problems, tiredness, and sleepiness. Dizziness or loss of muscle coordination. Call your healthcare provider right away if you have any of the symptoms above. The most common side effects of topiramate tablets include: tingling of the arms and legs (paresthesia) not feeling hungry nausea a change in the way foods taste diarrhea weight loss nervousness upper respiratory tract infection speech problems tiredness dizziness sleepiness/drowsiness slow reactions difficulty with memory pain in the abdomen fever abnormal vision Tell your healthcare provider about any side effect that bothers you or that does not go away. These are not all the possible side effects of topiramate tablets. For more information, ask your healthcare provider or pharmacist. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may also report side effects to Sun Pharmaceutical Industries, Inc. at 1-800-818-4555. How should I store topiramate tablets? Store topiramate tablets at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F). Keep topiramate tablets in a tightly closed container. Keep topiramate tablets dry and away from moisture. Keep topiramate tablets and all medicines out of the reach of children. General information about topiramate tablets . Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use topiramate tablets for a condition for which it was not prescribed. Do not give topiramate tablets to other people, even if they have the same symptoms that you have. It may harm them. This Medication Guide summarizes the most important information about topiramate tablets. If you would like more information, talk with your healthcare provider. You can ask your pharmacist or healthcare provider for information about topiramate tablets that is written for health professionals. For more information, call 1-800-818-4555. What are the ingredients in topiramate tablets? Active ingredient: topiramate Inactive ingredients: Anhydrous lactose, microcrystalline cellulose, pregelatinized maize starch, sodium starch glycolate type A potato, magnesium stearate, polyvinyl alcohol, titanium dioxide, polyethylene glycol and talc. In addition, individual tablets contain: 50 mg tablets: iron oxide yellow 100 mg tablets: iron oxide yellow, and D&C Yellow # 10 Aluminum Lake 200 mg tablets: iron oxide red, lecithin (soya), and iron oxide black Additional pediatric use information for patients ages 12 to 17 years is approved for Janssen Pharmaceuticals, Inc.’s TOPAMAX (topiramate) Tablets and Sprinkle Capsules. However, due to Janssen Pharmaceuticals, Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information. This Medication Guide has been approved by the U.S. Food and Drug Administration. * All trademark names are the property of their respective owners. Distributed by: Sun Pharmaceutical Industries, Inc. Cranbury, NJ 08512 Manufactured by: Sun Pharmaceutical Industries Limited Survey No. 259/15, Dadra-396 191, (U.T. of D & NH), India. ISS. 11/2015 PGPI0305D
Clinical studies
This field may contain references to clinical studies in place of detailed discussion in other sections of the labeling.14 CLINICAL STUDIES The studies described in the following sections were conducted using topiramate tablets. 14.1 Monotherapy Epilepsy Controlled Trial Patients with Partial Onset or Primary Generalized Tonic-Clonic Seizures Adults and Pediatric Patients 10 Years of Age and Older The effectiveness of topiramate as initial monotherapy in adults and children 10 years of age and older with partial onset or primary generalized tonic-clonic seizures was established in a multicenter, randomized, double-blind, parallel-group trial. The trial was conducted in 487 patients diagnosed with epilepsy (6 to 83 years of age) who had 1 or 2 well-documented seizures during the 3-month retrospective baseline phase who then entered the study and received topiramate 25 mg/day for 7 days in an open-label fashion. Forty-nine percent of patients had no prior AED treatment and 17% had a diagnosis of epilepsy for greater than 24 months. Any AED therapy used for temporary or emergency purposes was discontinued prior to randomization. In the double-blind phase, 470 patients were randomized to titrate up to 50 mg/day or 400 mg/day. If the target dose could not be achieved, patients were maintained on the maximum tolerated dose. Fifty-eight percent of patients achieved the maximal dose of 400 mg/day for >2 weeks, and patients who did not tolerate 150 mg/day were discontinued. The primary efficacy assessment was a between-group comparison of time to first seizure during the double-blind phase. Comparison of the Kaplan-Meier survival curves of time to first seizure favored the topiramate 400 mg/day group over the topiramate 50 mg/day group (p=0.0002, log rank test; Figure 1). The treatment effects with respect to time to first seizure were consistent across various patient subgroups defined by age, sex, geographic region, baseline body weight, baseline seizure type, time since diagnosis, and baseline AED use. Children 2 to <10 Years of Age The conclusion that topiramate is effective as initial monotherapy in children 2 to < 10 years of age with partial onset or primary generalized tonic-clonic seizures was based on a pharmacometric bridging approach using data from the controlled epilepsy trials described in labeling. This approach consisted of first showing a similar exposure response relationship between pediatric patients down to 2 years of age and adults when topiramate was given as adjunctive therapy. Similarity of exposure-response was also demonstrated in pediatric patients ages 6 to <16 years and adults when topiramate was given as initial monotherapy. Specific dosing in children 2 to <10 years of age was derived from simulations utilizing plasma exposure ranges observed in pediatric and adult patients treated with topiramate initial monotherapy [see Dosage and Administration ( 2.1 )] . figure-1 14.2 Adjunctive Therapy Epilepsy Controlled Trials Adult Patients With Partial Onset Seizures The effectiveness of topiramate as an adjunctive treatment for adults with partial onset seizures was established in six multicenter, randomized, double-blind, placebo-controlled trials, two comparing several dosages of topiramate and placebo and four comparing a single dosage with placebo, in patients with a history of partial onset seizures, with or without secondarily generalized seizures. Patients in these studies were permitted a maximum of two antiepileptic drugs (AEDs) in addition to topiramate tablets or placebo. In each study, patients were stabilized on optimum dosages of their concomitant AEDs during baseline phase lasting between 4 and 12 weeks. Patients who experienced a prespecified minimum number of partial onset seizures, with or without secondary generalization, during the baseline phase (12 seizures for 12-week baseline, 8 for 8-week baseline or 3 for 4-week baseline) were randomly assigned to placebo or a specified dose of topiramate tablets in addition to their other AEDs. Following randomization, patients began the double-blind phase of treatment. In five of the six studies, patients received active drug beginning at 100 mg per day; the dose was then increased by 100 mg or 200 mg/day increments weekly or every other week until the assigned dose was reached, unless intolerance prevented increases. In the sixth study (119), the 25 or 50 mg/day initial doses of topiramate were followed by respective weekly increments of 25 or 50 mg/day until the target dose of 200 mg/day was reached. After titration, patients entered a 4, 8 or 12-week stabilization period. The numbers of patients randomized to each dose and the actual mean and median doses in the stabilization period are shown in Table 14. Pediatric Patients Ages 2 to 16 Years with Partial Onset Seizures The effectiveness of topiramate as an adjunctive treatment for pediatric patients ages 2 to 16 years with partial onset seizures was established in a multicenter, randomized, double-blind, placebo-controlled trial(Study YP), comparing topiramate and placebo in patients with a history of partial onset seizures, with or without secondarily generalized seizures (see Table 15). Patients in this study were permitted a maximum of two antiepileptic drugs (AEDs) in addition to topiramate tablets or placebo. In this study, patients were stabilized on optimum dosages of their concomitant AEDs during an 8-week baseline phase. Patients who experienced at least six partial onset seizures, with or without secondarily generalized seizures, during the baseline phase were randomly assigned to placebo or topiramate tablets in addition to their other AEDs. Following randomization, patients began the double-blind phase of treatment. Patients received active drug beginning at 25 or 50 mg/day; the dose was then increased by 25 mg to 150 mg/day increments every other week until the assigned dosage of 125, 175, 225, or 400 mg/day based on patients' weight to approximate a dosage of 6 mg/kg/day was reached, unless intolerance prevented increases. After titration, patients entered an 8-week stabilization period. Patients With Primary Generalized Tonic-Clonic Seizures The effectiveness of topiramate as an adjunctive treatment for primary generalized tonic-clonic seizures in patients 2 years old and older was established in a multicenter, randomized, double-blind, placebo-controlled trial, (Study YTC), comparing a single dosage of topiramate and placebo (see Table 15). Patients in this study were permitted a maximum of two antiepileptic drugs (AEDs) in addition to topiramate or placebo. Patients were stabilized on optimum dosages of their concomitant AEDs during an 8-week baseline phase. Patients who experienced at least three primary generalized tonic-clonic seizures during the baseline phase were randomly assigned to placebo or topiramate in addition to their other AEDs. Following randomization, patients began the double-blind phase of treatment. Patients received active drug beginning at 50 mg/day for four weeks; the dose was then increased by 50 mg to 150 mg/day increments every other week until the assigned dose of 175, 225, or 400 mg/day based on patients' body weight to approximate a dosage of 6 mg/kg/day was reached, unless intolerance prevented increases. After titration, patients entered a 12-week stabilization period. Patients With Lennox-Gastaut Syndrome The effectiveness of topiramate as an adjunctive treatment for seizures associated with Lennox-Gastaut syndrome was established in a multicenter, randomized, double-blind, placebo-controlled trial (Study YL) comparing a single dosage of topiramate with placebo in patients 2 years of age and older (see Table 15). Patients in this study were permitted a maximum of two antiepileptic drugs (AEDs) in addition to topiramate or placebo. Patients who were experiencing at least 60 seizures per month before study entry were stabilized on optimum dosages of their concomitant AEDs during a 4-week baseline phase. Following baseline, patients were randomly assigned to placebo or topiramate in addition to their other AEDs. Active drug was titrated beginning at 1 mg/kg/day for a week; the dose was then increased to 3 mg/kg/day for one week, then to 6 mg/kg/day. After titration, patients entered an 8-week stabilization period. The primary measures of effectiveness were the percent reduction in drop attacks and a parental global rating of seizure severity. Table 14: Topiramate Dose Summary During the Stabilization Periods of Each of Six Double-Blind, Placebo-Controlled, Add-On Trials in Adults with Partial Onset Seizures Dose-response studies were not conducted for other indications or pediatric partial onset seizures Target Topiramate Dosage (mg/day) Protocol Stabilization Dose Placebo Placebo dosages are given as the number of tablets. Placebo target dosages were as follows: 200 400 600 800 1,000 YD N 42 42 40 41 -- -- Mean Dose 5.9 200 390 556 -- -- Median Dose 6 200 400 600 -- -- YE N 44 -- -- 40 45 40 Mean Dose 9.7 -- -- 544 739 796 Median Dose 10 -- -- 600 800 1,000 Y1 N 23 -- 19 -- -- -- Mean Dose 3.8 -- 395 -- -- -- Median Dose 4 -- 400 -- -- -- Y2 N 30 -- -- 28 -- -- Mean Dose 5.7 -- -- 522 -- -- Median Dose 6 -- -- 600 -- -- Y3 N 28 -- -- -- 25 -- Mean Dose 7.9 -- -- -- 568 -- Median Dose 8 -- -- -- 600 -- 119 N 90 157 -- -- -- -- Mean Dose 8 200 -- -- -- -- Median Dose 8 200 -- -- -- -- Protocol Y1, 4 tablets/day; Protocols YD and Y2, 6 tablets/day; Protocols Y3 and 119, 8 tablets/day; Protocol YE, 10 tablets/day. In all add-on trials, the reduction in seizure rate from baseline during the entire double-blind phase was measured. The median percent reductions in seizure rates and the responder rates (fraction of patients with at least a 50% reduction) by treatment group for each study are shown below in Table 15. As described above, a global improvement in seizure severity was also assessed in the Lennox-Gastaut trial. Table 15: Efficacy Results in Double-Blind, Placebo-Controlled, Add-On Epilepsy Trials Protocol Efficacy Results Placebo Target Topiramate Dosage (mg/day) 200 400 600 800 1,000 ≈6 mg/kg/day* Partial Onset Seizures Studies in Adults YD N 45 45 45 46 -- -- -- Median % Reduction 11.6 27.2 a 47.5 b 44.7 c -- -- -- % Responders 18 24 44 d 46 d -- -- -- YE N 47 -- -- 48 48 47 -- Median % Reduction 1.7 -- -- 40.8 c 41 c 36 c -- % Responders 9 -- -- 40 c 41 c 36 d -- Y1 N 24 -- 23 -- -- -- -- Median % Reduction 1.1 -- 40.7 e -- -- -- -- % Responders 8 -- 35 d -- -- -- -- Y2 N 30 -- -- 30 -- -- -- Median % Reduction -12.2 -- -- 46.4 f -- -- -- % Responders 10 -- -- 47 c -- -- -- Y3 N 28 -- -- -- 28 -- -- Median % Reduction -20.6 -- -- -- 24.3 c -- -- % Responders 0 -- -- -- 43 c -- -- 119 N 91 168 -- -- -- -- -- Median % Reduction 20 44.2 c -- -- -- -- -- % Responders 24 45 c -- -- -- -- -- Studies in Pediatric Patients YP N 45 -- -- -- -- -- 41 Median % Reduction 10.5 -- -- -- -- -- 33.1 d % Responders 20 -- -- -- -- -- 39 Primary Generalized Tonic-Clonic h YTC N 40 -- -- -- -- -- 39 Median % Reduction 9 -- -- -- -- -- 56.7 d % Responders 20 -- -- -- -- -- 56 c Lennox-Gastaut Syndrome i YL N 49 -- -- -- -- -- 46 Median % Reduction -5.1 -- -- -- -- -- 14.8 d % Responders 14 -- -- -- -- -- 28 g Improvement in Seizure Severity j 28 -- -- -- -- -- 52 d Comparisons with placebo: a p=0.08; b p≤0.01; c p≤0.001; d p≤0.05; e p=0.065; f p≤0.005; g p=0.071; h Median % reduction and % responders are reported for PGTC Seizures; i Median % reduction and % responders for drop attacks, i.e., tonic or atonic seizures; j Percent of patients who were minimally, much, or very much improved from baseline * For Protocols YP and YTC, protocol-specified target dosages (<9.3 mg/kg/day) were assigned based on subject's weight to approximate a dosage of 6 mg/kg per day; these dosages corresponded to mg/day dosages of 125, 175, 225, and 400 mg/day. Subset analyses of the antiepileptic efficacy of topiramate tablets in these studies showed no differences as a function of gender, race, age, baseline seizure rate, or concomitant AED. In clinical trials for epilepsy, daily dosages were decreased in weekly intervals by 50 to 100 mg/day in adults and over a 2- to 8-week period in children; transition was permitted to a new antiepileptic regimen when clinically indicated. Additional pediatric use information for patients ages 12 to 17 years is approved for Janssen Pharmaceuticals, Inc.’s TOPAMAX (topiramate) Tablets and Sprinkle Capsules. However, due to Janssen Pharmaceuticals, Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information.
| Target Topiramate Dosage (mg/day) | ||||||||
| Protocol | ||||||||
| Stabilization Dose | Placebo | 200 | 400 | 600 | 800 | 1,000 | ||
| YD | N | 42 | 42 | 40 | 41 | -- | -- | |
| Mean Dose | 5.9 | 200 | 390 | 556 | -- | -- | ||
| Median Dose | 6 | 200 | 400 | 600 | -- | -- | ||
| YE | N | 44 | -- | -- | 40 | 45 | 40 | |
| Mean Dose | 9.7 | -- | -- | 544 | 739 | 796 | ||
| Median Dose | 10 | -- | -- | 600 | 800 | 1,000 | ||
| Y1 | N | 23 | -- | 19 | -- | -- | -- | |
| Mean Dose | 3.8 | -- | 395 | -- | -- | -- | ||
| Median Dose | 4 | -- | 400 | -- | -- | -- | ||
| Y2 | N | 30 | -- | -- | 28 | -- | -- | |
| Mean Dose | 5.7 | -- | -- | 522 | -- | -- | ||
| Median Dose | 6 | -- | -- | 600 | -- | -- | ||
| Y3 | N | 28 | -- | -- | -- | 25 | -- | |
| Mean Dose | 7.9 | -- | -- | -- | 568 | -- | ||
| Median Dose | 8 | -- | -- | -- | 600 | -- | ||
| 119 | N | 90 | 157 | -- | -- | -- | -- | |
| Mean Dose | 8 | 200 | -- | -- | -- | -- | ||
| Median Dose | 8 | 200 | -- | -- | -- | -- | ||
| Partial Onset Seizures | ||||||||
| Studies in Adults | ||||||||
| YD N | 45 | 45 | 45 | 46 | -- | -- | -- | |
| Median % Reduction | 11.6 | 27.2 a | 47.5 b | 44.7 c | -- | -- | -- | |
| % Responders | 18 | 24 | 44 d | 46 d | -- | -- | -- | |
| YE N | 47 | -- | -- | 48 | 48 | 47 | -- | |
| Median % Reduction | 1.7 | -- | -- | 40.8 c | 41 c | 36 c | -- | |
| % Responders | 9 | -- | -- | 40 c | 41 c | 36 d | -- | |
| Y1 N | 24 | -- | 23 | -- | -- | -- | -- | |
| Median % Reduction | 1.1 | -- | 40.7 e | -- | -- | -- | -- | |
| % Responders | 8 | -- | 35 d | -- | -- | -- | -- | |
| Y2 N | 30 | -- | -- | 30 | -- | -- | -- | |
| Median % Reduction | -12.2 | -- | -- | 46.4 f | -- | -- | -- | |
| % Responders | 10 | -- | -- | 47 c | -- | -- | -- | |
| Y3 N | 28 | -- | -- | -- | 28 | -- | -- | |
| Median % Reduction | -20.6 | -- | -- | -- | 24.3 c | -- | -- | |
| % Responders | 0 | -- | -- | -- | 43 c | -- | -- | |
| 119 N | 91 | 168 | -- | -- | -- | -- | -- | |
| Median % Reduction | 20 | 44.2 c | -- | -- | -- | -- | -- | |
| % Responders | 24 | 45 c | -- | -- | -- | -- | -- | |
| Studies in Pediatric Patients | ||||||||
| YP N | 45 | -- | -- | -- | -- | -- | 41 | |
| Median % Reduction | 10.5 | -- | -- | -- | -- | -- | 33.1 d | |
| % Responders | 20 | -- | -- | -- | -- | -- | 39 | |
| Primary Generalized Tonic-Clonic h | ||||||||
| YTC N | 40 | -- | -- | -- | -- | -- | 39 | |
| Median % Reduction | 9 | -- | -- | -- | -- | -- | 56.7 d | |
| % Responders | 20 | -- | -- | -- | -- | -- | 56 c | |
| Lennox-Gastaut Syndrome i | ||||||||
| YL N | 49 | -- | -- | -- | -- | -- | 46 | |
| Median % Reduction | -5.1 | -- | -- | -- | -- | -- | 14.8 d | |
| % Responders | 14 | -- | -- | -- | -- | -- | 28 g | |
| Improvement in Seizure Severity j | 28 | -- | -- | -- | -- | -- | 52 d | |
Geriatric use
Information about any limitations on any geriatric indications, needs for specific monitoring, hazards associated with use of the drug in the geriatric population.8.5 Geriatric Use In clinical trials, 3% of patients were over 60. No age-related differences in effectiveness or adverse effects were evident. However, clinical studies of topiramate did not include sufficient numbers of subjects age 65 and over to determine whether they respond differently than younger subjects. Dosage adjustment may be necessary for elderly with impaired renal function (creatinine clearance rate <70 mL/min/1.73 m 2 ) due to reduced clearance of topiramate [see Clinical Pharmacology ( 12.3 ) and Dosage and Administration ( 2.5 )] .
Labor and delivery
Information about the drug’s use during labor or delivery, whether or not the use is stated in the indications section of the labeling, including the effect of the drug on the mother and fetus, on the duration of labor or delivery, on the possibility of delivery-related interventions, and the effect of the drug on the later growth, development, and functional maturation of the child.8.2 Labor and Delivery Although the effect of topiramate on labor and delivery in humans has not been established, the development of topiramate-induced metabolic acidosis in the mother and/or in the fetus might affect the fetus’ ability to tolerate labor [see Use in Specific Populations ( 8.1 )] .
Nursing mothers
Information about excretion of the drug in human milk and effects on the nursing infant, including pertinent adverse effects observed in animal offspring.8.3 Nursing Mothers Limited data on 5 breastfeeding infants exposed to topiramate showed infant plasma topiramate levels equal to 10 to 20% of the maternal plasma level. The effects of this exposure on infants are unknown. Caution should be exercised when administered to a nursing woman.
Pediatric use
Information about any limitations on any pediatric indications, needs for specific monitoring, hazards associated with use of the drug in any subsets of the pediatric population (such as neonates, infants, children, or adolescents), differences between pediatric and adult responses to the drug, and other information related to the safe and effective pediatric use of the drug.8.4 Pediatric Use Adjunctive Treatment for Partial Onset Epilepsy in Infants and Toddlers (1 to 24 months) Safety and effectiveness in patients below the age of 2 years have not been established for the adjunctive therapy treatment of partial onset seizures, primary generalized tonic-clonic seizures, or seizures associated with Lennox-Gastaut syndrome. In a single randomized, double-blind, placebo-controlled investigational trial, the efficacy, safety, and tolerability of topiramate oral liquid and sprinkle formulations as an adjunct to concurrent antiepileptic drug therapy in infants 1 to 24 months of age with refractory partial onset seizures were assessed. After 20 days of double-blind treatment, topiramate (at fixed doses of 5, 15, and 25 mg/kg/day) did not demonstrate efficacy compared with placebo in controlling seizures. In general, the adverse reaction profile in this population was similar to that of older pediatric patients, although results from the above controlled study and an open-label, long-term extension study in these infants/toddlers (1 to 24 months old) suggested some adverse reactions/toxicities (not previously observed in older pediatric patients and adults; i.e., growth/length retardation, certain clinical laboratory abnormalities, and other adverse reactions/toxicities that occurred with a greater frequency and/or greater severity than had been recognized previously from studies in older pediatric patients or adults for various indications. These very young pediatric patients appeared to experience an increased risk for infections (any topiramate dose 12%, placebo 0%) and of respiratory disorders (any topiramate dose 40%, placebo 16%). The following adverse reactions were observed in at least 3% of patients on topiramate and were 3% to 7% more frequent than in patients on placebo: viral infection, bronchitis, pharyngitis, rhinitis, otitis media, upper respiratory infection, cough, and bronchospasm. A generally similar profile was observed in older children [see Adverse Reactions ( 6 )] . Topiramate resulted in an increased incidence of patients with increased creatinine (any topiramate dose 5%, placebo 0%), BUN (any topiramate dose 3%, placebo 0%), and protein (any topiramate dose 34%, placebo 6%), and an increased incidence of decreased potassium (any topiramate dose 7%, placebo 0%). This increased frequency of abnormal values was not dose-related. Creatinine was the only analyte showing a noteworthy increased incidence (topiramate 25 mg/kg/day 5%, placebo 0%) of a markedly abnormal increase [see Warnings and Precautions ( 5.16 )] . The significance of these findings is uncertain. Topiramate treatment also produced a dose-related increase in the percentage of patients who had a shift from normal at baseline to high/increased (above the normal reference range) in total eosinophil count at the end of treatment. The incidence of these abnormal shifts was 6 % for placebo, 10% for 5 mg/kg/day, 9% for 15 mg/kg/day, 14% for 25 mg/kg/day, and 11% for any topiramate dose [see Warnings and Precautions ( 5.16 )] . There was a mean dose-related increase in alkaline phosphatase. The significance of these findings is uncertain. Topiramate produced a dose-related increased incidence of treatment-emergent hyperammonemia [see Warnings and Precautions ( 5.10 )] . Treatment with topiramate for up to 1 year was associated with reductions in Z SCORES for length, weight, and head circumference [see Warnings and Precautions ( 5.4 ) and Adverse Reactions ( 6 )] . In open-label, uncontrolled experience, increasing impairment of adaptive behavior was documented in behavioral testing over time in this population. There was a suggestion that this effect was dose-related. However, because of the absence of an appropriate control group, it is not known if this decrement in function was treatment-related or reflects the patient’s underlying disease (e.g., patients who received higher doses may have more severe underlying disease) [see Warnings and Precautions ( 5.6 )] . In this open-label, uncontrolled study, the mortality was 37 deaths/1,000 patient years. It is not possible to know whether this mortality rate is related to topiramate treatment, because the background mortality rate for a similar, significantly refractory, young pediatric population (1 to 24 months) with partial epilepsy is not known. Monotherapy Treatment in Partial Onset Epilepsy in Patients <2 Years Old Safety and effectiveness in patients below the age of 2 years have not been established for the monotherapy treatment of epilepsy. Additional pediatric use information for patients ages 12 to 17 years is approved for Janssen Pharmaceuticals, Inc.’s TOPAMAX (topiramate) Tablets and Sprinkle Capsules. However, due to Janssen Pharmaceuticals, Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information. Juvenile Animal Studies When topiramate (30, 90, or 300 mg/kg/day) was administered orally to rats during the juvenile period of development (postnatal days 12 to 50), bone growth plate thickness was reduced in males at the highest dose, which is approximately 5 to 8 times the maximum recommended pediatric dose (9 mg/kg/day) on a body surface area (mg/m 2 ) basis.
Pregnancy
Information about effects the drug may have on pregnant women or on a fetus. This field may be ommitted if the drug is not absorbed systemically and the drug is not known to have a potential for indirect harm to the fetus. It may contain information about the established pregnancy category classification for the drug. (That information is nominally listed in the teratogenic_effects field, but may be listed here instead.)8.1 Pregnancy Pregnancy Category D. [see Warnings and Precautions ( 5.7 )] Topiramate can cause fetal harm when administered to a pregnant woman. Data from pregnancy registries indicate that infants exposed to topiramate in utero have an increased risk for cleft lip and/or cleft palate (oral clefts). When multiple species of pregnant animals received topiramate at clinically relevant doses, structural malformations, including craniofacial defects, and reduced fetal weights occurred in offspring. Topiramate should be used during pregnancy only if the potential benefit outweighs the potential risk. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to a fetus [see Use in Specific Populations ( 8.9 )] . Pregnancy Registry Patients should be encouraged to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry if they become pregnant. This registry is collecting information about the safety of antiepileptic drugs during pregnancy. To enroll, patients can call the toll-free number 1-888-233-2334. Information about the North American Drug Pregnancy Registry can be found at http://www.massgeneral.org/aed/ . Human Data Data from the NAAED Pregnancy Registry (425 prospective topiramate monotherapy-exposed pregnancies) indicate an increased risk of oral clefts in infants exposed during the first trimester of pregnancy. The prevalence of oral clefts among topiramate-exposed infants was 1.2% compared to a prevalence of 0.39% for infants exposed to a reference AED. In infants of mothers without epilepsy or treatment with other AEDs, the prevalence was 0.12%. For comparison, the Centers for Disease Control and Prevention (CDC) reviewed available data on oral clefts in the United States and found a similar background rate of 0.17%. The relative risk of oral clefts in topiramate-exposed pregnancies in the NAAED Pregnancy Registry was 9.6 (95% Confidence Interval [CI] 4 to 23) as compared to the risk in a background population of untreated women. The UK Epilepsy and Pregnancy Register reported a similarly increased prevalence of oral clefts of 3.2% among infants exposed to topiramate monotherapy. The observed rate of oral clefts was 16 times higher than the background rate in the UK, which is approximately 0.2%. Topiramate treatment can cause metabolic acidosis [see Warnings and Precautions ( 5.4 )] . The effect of topiramate-induced metabolic acidosis has not been studied in pregnancy; however, metabolic acidosis in pregnancy (due to other causes) can cause decreased fetal growth, decreased fetal oxygenation, and fetal death, and may affect the fetus’ ability to tolerate labor. Pregnant patients should be monitored for metabolic acidosis and treated as in the nonpregnant state [see Warnings and Precautions ( 5.4 )] . Newborns of mothers treated with topiramate should be monitored for metabolic acidosis because of transfer of topiramate to the fetus and possible occurrence of transient metabolic acidosis following birth. Animal Data Topiramate has demonstrated selective developmental toxicity, including teratogenicity, in multiple animal species at clinically relevant doses. When oral doses of 20, 100, or 500 mg/kg were administered to pregnant mice during the period of organogenesis, the incidence of fetal malformations (primarily craniofacial defects) was increased at all doses. The low dose is approximately 0.2 times the recommended human dose (RHD) 400 mg/day on a mg/m 2 basis. Fetal body weights and skeletal ossification were reduced at 500 mg/kg in conjunction with decreased maternal body weight gain. In rat studies (oral doses of 20, 100, and 500 mg/kg or 0.2, 2.5, 30, and 400 mg/kg), the frequency of limb malformations (ectrodactyly, micromelia, and amelia) was increased among the offspring of dams treated with 400 mg/kg (10 times the RHD on a mg/m 2 basis) or greater during the organogenesis period of pregnancy. Embryotoxicity (reduced fetal body weights, increased incidence of structural variations) was observed at doses as low as 20 mg/kg (0.5 times the RHD on a mg/m 2 basis). Clinical signs of maternal toxicity were seen at 400 mg/kg and above, and maternal body weight gain was reduced during treatment with 100 mg/kg or greater. In rabbit studies (20, 60, and 180 mg/kg or 10, 35, and 120 mg/kg orally during organogenesis), embryo/fetal mortality was increased at 35 mg/kg (2 times the RHD on a mg/m 2 basis) or greater, and teratogenic effects (primarily rib and vertebral malformations) were observed at 120 mg/kg (6 times the RHD on a mg/m 2 basis). Evidence of maternal toxicity (decreased body weight gain, clinical signs, and/or mortality) was seen at 35 mg/kg and above. When female rats were treated during the latter part of gestation and throughout lactation (0.2, 4, 20, and 100 mg/kg or 2, 20, and 200 mg/kg), offspring exhibited decreased viability and delayed physical development at 200 mg/kg (5 times the RHD on a mg/m 2 basis) and reductions in pre-and/or postweaning body weight gain at 2 mg/kg (0.05 times the RHD on a mg/m 2 basis) and above. Maternal toxicity (decreased body weight gain, clinical signs) was evident at 100 mg/kg or greater. In a rat embryo/fetal development study with a postnatal component (0.2, 2.5, 30, or 400 mg/kg during organogenesis; noted above), pups exhibited delayed physical development at 400 mg/kg (10 times the RHD on a mg/m 2 basis) and persistent reductions in body weight gain at 30 mg/kg (1 times the RHD on a mg/m 2 basis) and higher.
Use in specific populations
Information about use of the drug by patients in specific populations, including pregnant women and nursing mothers, pediatric patients, and geriatric patients.8 USE IN SPECIFIC POPULATIONS Renal impairment: In renally impaired patients (creatinine clearance less than 70 mL/min/1.73 m 2 ), one-half of the adult dose is recommended ( 2.4 ) Patients undergoing hemodialysis: Topiramate is cleared by hemodialysis. Dosage adjustment is necessary to avoid rapid drops in topiramate plasma concentration during hemodialysis ( 2.6 ) Pregnancy: Increased risk of cleft lip and/or palate. ( 8.1 ) Nursing mothers: Caution should be exercised when administered to a nursing mother ( 8.3 ) Geriatric use: Dosage adjustment may be necessary for elderly with impaired renal function ( 8.5 ) Additional pediatric use information for patients ages 12 to 17 years is approved for Janssen Pharmaceuticals, Inc.’s TOPAMAX (topiramate) Tablets and Sprinkle Capsules. However, due to Janssen Pharmaceuticals, Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information. 8.1 Pregnancy Pregnancy Category D. [see Warnings and Precautions ( 5.7 )] Topiramate can cause fetal harm when administered to a pregnant woman. Data from pregnancy registries indicate that infants exposed to topiramate in utero have an increased risk for cleft lip and/or cleft palate (oral clefts). When multiple species of pregnant animals received topiramate at clinically relevant doses, structural malformations, including craniofacial defects, and reduced fetal weights occurred in offspring. Topiramate should be used during pregnancy only if the potential benefit outweighs the potential risk. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to a fetus [see Use in Specific Populations ( 8.9 )] . Pregnancy Registry Patients should be encouraged to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry if they become pregnant. This registry is collecting information about the safety of antiepileptic drugs during pregnancy. To enroll, patients can call the toll-free number 1-888-233-2334. Information about the North American Drug Pregnancy Registry can be found at http://www.massgeneral.org/aed/ . Human Data Data from the NAAED Pregnancy Registry (425 prospective topiramate monotherapy-exposed pregnancies) indicate an increased risk of oral clefts in infants exposed during the first trimester of pregnancy. The prevalence of oral clefts among topiramate-exposed infants was 1.2% compared to a prevalence of 0.39% for infants exposed to a reference AED. In infants of mothers without epilepsy or treatment with other AEDs, the prevalence was 0.12%. For comparison, the Centers for Disease Control and Prevention (CDC) reviewed available data on oral clefts in the United States and found a similar background rate of 0.17%. The relative risk of oral clefts in topiramate-exposed pregnancies in the NAAED Pregnancy Registry was 9.6 (95% Confidence Interval [CI] 4 to 23) as compared to the risk in a background population of untreated women. The UK Epilepsy and Pregnancy Register reported a similarly increased prevalence of oral clefts of 3.2% among infants exposed to topiramate monotherapy. The observed rate of oral clefts was 16 times higher than the background rate in the UK, which is approximately 0.2%. Topiramate treatment can cause metabolic acidosis [see Warnings and Precautions ( 5.4 )] . The effect of topiramate-induced metabolic acidosis has not been studied in pregnancy; however, metabolic acidosis in pregnancy (due to other causes) can cause decreased fetal growth, decreased fetal oxygenation, and fetal death, and may affect the fetus’ ability to tolerate labor. Pregnant patients should be monitored for metabolic acidosis and treated as in the nonpregnant state [see Warnings and Precautions ( 5.4 )] . Newborns of mothers treated with topiramate should be monitored for metabolic acidosis because of transfer of topiramate to the fetus and possible occurrence of transient metabolic acidosis following birth. Animal Data Topiramate has demonstrated selective developmental toxicity, including teratogenicity, in multiple animal species at clinically relevant doses. When oral doses of 20, 100, or 500 mg/kg were administered to pregnant mice during the period of organogenesis, the incidence of fetal malformations (primarily craniofacial defects) was increased at all doses. The low dose is approximately 0.2 times the recommended human dose (RHD) 400 mg/day on a mg/m 2 basis. Fetal body weights and skeletal ossification were reduced at 500 mg/kg in conjunction with decreased maternal body weight gain. In rat studies (oral doses of 20, 100, and 500 mg/kg or 0.2, 2.5, 30, and 400 mg/kg), the frequency of limb malformations (ectrodactyly, micromelia, and amelia) was increased among the offspring of dams treated with 400 mg/kg (10 times the RHD on a mg/m 2 basis) or greater during the organogenesis period of pregnancy. Embryotoxicity (reduced fetal body weights, increased incidence of structural variations) was observed at doses as low as 20 mg/kg (0.5 times the RHD on a mg/m 2 basis). Clinical signs of maternal toxicity were seen at 400 mg/kg and above, and maternal body weight gain was reduced during treatment with 100 mg/kg or greater. In rabbit studies (20, 60, and 180 mg/kg or 10, 35, and 120 mg/kg orally during organogenesis), embryo/fetal mortality was increased at 35 mg/kg (2 times the RHD on a mg/m 2 basis) or greater, and teratogenic effects (primarily rib and vertebral malformations) were observed at 120 mg/kg (6 times the RHD on a mg/m 2 basis). Evidence of maternal toxicity (decreased body weight gain, clinical signs, and/or mortality) was seen at 35 mg/kg and above. When female rats were treated during the latter part of gestation and throughout lactation (0.2, 4, 20, and 100 mg/kg or 2, 20, and 200 mg/kg), offspring exhibited decreased viability and delayed physical development at 200 mg/kg (5 times the RHD on a mg/m 2 basis) and reductions in pre-and/or postweaning body weight gain at 2 mg/kg (0.05 times the RHD on a mg/m 2 basis) and above. Maternal toxicity (decreased body weight gain, clinical signs) was evident at 100 mg/kg or greater. In a rat embryo/fetal development study with a postnatal component (0.2, 2.5, 30, or 400 mg/kg during organogenesis; noted above), pups exhibited delayed physical development at 400 mg/kg (10 times the RHD on a mg/m 2 basis) and persistent reductions in body weight gain at 30 mg/kg (1 times the RHD on a mg/m 2 basis) and higher. 8.2 Labor and Delivery Although the effect of topiramate on labor and delivery in humans has not been established, the development of topiramate-induced metabolic acidosis in the mother and/or in the fetus might affect the fetus’ ability to tolerate labor [see Use in Specific Populations ( 8.1 )] . 8.3 Nursing Mothers Limited data on 5 breastfeeding infants exposed to topiramate showed infant plasma topiramate levels equal to 10 to 20% of the maternal plasma level. The effects of this exposure on infants are unknown. Caution should be exercised when administered to a nursing woman. 8.4 Pediatric Use Adjunctive Treatment for Partial Onset Epilepsy in Infants and Toddlers (1 to 24 months) Safety and effectiveness in patients below the age of 2 years have not been established for the adjunctive therapy treatment of partial onset seizures, primary generalized tonic-clonic seizures, or seizures associated with Lennox-Gastaut syndrome. In a single randomized, double-blind, placebo-controlled investigational trial, the efficacy, safety, and tolerability of topiramate oral liquid and sprinkle formulations as an adjunct to concurrent antiepileptic drug therapy in infants 1 to 24 months of age with refractory partial onset seizures were assessed. After 20 days of double-blind treatment, topiramate (at fixed doses of 5, 15, and 25 mg/kg/day) did not demonstrate efficacy compared with placebo in controlling seizures. In general, the adverse reaction profile in this population was similar to that of older pediatric patients, although results from the above controlled study and an open-label, long-term extension study in these infants/toddlers (1 to 24 months old) suggested some adverse reactions/toxicities (not previously observed in older pediatric patients and adults; i.e., growth/length retardation, certain clinical laboratory abnormalities, and other adverse reactions/toxicities that occurred with a greater frequency and/or greater severity than had been recognized previously from studies in older pediatric patients or adults for various indications. These very young pediatric patients appeared to experience an increased risk for infections (any topiramate dose 12%, placebo 0%) and of respiratory disorders (any topiramate dose 40%, placebo 16%). The following adverse reactions were observed in at least 3% of patients on topiramate and were 3% to 7% more frequent than in patients on placebo: viral infection, bronchitis, pharyngitis, rhinitis, otitis media, upper respiratory infection, cough, and bronchospasm. A generally similar profile was observed in older children [see Adverse Reactions ( 6 )] . Topiramate resulted in an increased incidence of patients with increased creatinine (any topiramate dose 5%, placebo 0%), BUN (any topiramate dose 3%, placebo 0%), and protein (any topiramate dose 34%, placebo 6%), and an increased incidence of decreased potassium (any topiramate dose 7%, placebo 0%). This increased frequency of abnormal values was not dose-related. Creatinine was the only analyte showing a noteworthy increased incidence (topiramate 25 mg/kg/day 5%, placebo 0%) of a markedly abnormal increase [see Warnings and Precautions ( 5.16 )] . The significance of these findings is uncertain. Topiramate treatment also produced a dose-related increase in the percentage of patients who had a shift from normal at baseline to high/increased (above the normal reference range) in total eosinophil count at the end of treatment. The incidence of these abnormal shifts was 6 % for placebo, 10% for 5 mg/kg/day, 9% for 15 mg/kg/day, 14% for 25 mg/kg/day, and 11% for any topiramate dose [see Warnings and Precautions ( 5.16 )] . There was a mean dose-related increase in alkaline phosphatase. The significance of these findings is uncertain. Topiramate produced a dose-related increased incidence of treatment-emergent hyperammonemia [see Warnings and Precautions ( 5.10 )] . Treatment with topiramate for up to 1 year was associated with reductions in Z SCORES for length, weight, and head circumference [see Warnings and Precautions ( 5.4 ) and Adverse Reactions ( 6 )] . In open-label, uncontrolled experience, increasing impairment of adaptive behavior was documented in behavioral testing over time in this population. There was a suggestion that this effect was dose-related. However, because of the absence of an appropriate control group, it is not known if this decrement in function was treatment-related or reflects the patient’s underlying disease (e.g., patients who received higher doses may have more severe underlying disease) [see Warnings and Precautions ( 5.6 )] . In this open-label, uncontrolled study, the mortality was 37 deaths/1,000 patient years. It is not possible to know whether this mortality rate is related to topiramate treatment, because the background mortality rate for a similar, significantly refractory, young pediatric population (1 to 24 months) with partial epilepsy is not known. Monotherapy Treatment in Partial Onset Epilepsy in Patients <2 Years Old Safety and effectiveness in patients below the age of 2 years have not been established for the monotherapy treatment of epilepsy. Additional pediatric use information for patients ages 12 to 17 years is approved for Janssen Pharmaceuticals, Inc.’s TOPAMAX (topiramate) Tablets and Sprinkle Capsules. However, due to Janssen Pharmaceuticals, Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information. Juvenile Animal Studies When topiramate (30, 90, or 300 mg/kg/day) was administered orally to rats during the juvenile period of development (postnatal days 12 to 50), bone growth plate thickness was reduced in males at the highest dose, which is approximately 5 to 8 times the maximum recommended pediatric dose (9 mg/kg/day) on a body surface area (mg/m 2 ) basis. 8.5 Geriatric Use In clinical trials, 3% of patients were over 60. No age-related differences in effectiveness or adverse effects were evident. However, clinical studies of topiramate did not include sufficient numbers of subjects age 65 and over to determine whether they respond differently than younger subjects. Dosage adjustment may be necessary for elderly with impaired renal function (creatinine clearance rate <70 mL/min/1.73 m 2 ) due to reduced clearance of topiramate [see Clinical Pharmacology ( 12.3 ) and Dosage and Administration ( 2.5 )] . 8.6 Race and Gender Effects Evaluation of effectiveness and safety in clinical trials has shown no race- or gender-related effects. 8.7 Renal Impairment The clearance of topiramate was reduced by 42% in moderately renally impaired (creatinine clearance 30 to 69 mL/min/1.73 m 2 ) and by 54% in severely renally impaired subjects (creatinine clearance <30 mL/min/1.73 m 2 ) compared to normal renal function subjects (creatinine clearance >70 mL/min/1.73 m 2 ). One-half the usual starting and maintenance dose is recommended in patients with moderate or severe renal impairment [see Dosage and Administration ( 2.6 ) and Clinical Pharmacology ( 12.3 )] . 8.8 Patients Undergoing Hemodialysis Topiramate is cleared by hemodialysis at a rate that is 4 to 6 times greater than in a normal individual. Accordingly, a prolonged period of dialysis may cause topiramate concentration to fall below that required to maintain an anti-seizure effect. To avoid rapid drops in topiramate plasma concentration during hemodialysis, a supplemental dose of topiramate may be required. The actual adjustment should take into account the duration of dialysis period, the clearance rate of the dialysis system being used, and the effective renal clearance of topiramate in the patient being dialyzed [see Dosage and Administration ( 2.4 ) and Clinical Pharmacology ( 12.3 )] . 8.9 Women of Childbearing Potential Data from pregnancy registries indicate that infants exposed to topiramate in utero have an increased risk for cleft lip and/or cleft palate (oral clefts) [see Warnings and Precautions ( 5.7 ) and Use in Specific Populations ( 8.1 )] . Consider the benefits and the risks of topiramate when prescribing this drug to women of childbearing potential, particularly when topiramate is considered for a condition not usually associated with permanent injury or death. Because of the risk of oral clefts to the fetus, which occur in the first trimester of pregnancy before many women know they are pregnant, all women of childbearing potential should be apprised of the potential hazard to the fetus from exposure to topiramate. If the decision is made to use topiramate, women who are not planning a pregnancy should use effective contraception [see Drug Interactions ( 7.3 )] . Women who are planning a pregnancy should be counseled regarding the relative risks and benefits of topiramate use during pregnancy, and alternative therapeutic options should be considered for these patients.
How supplied
Information about the available dosage forms to which the labeling applies, and for which the manufacturer or distributor is responsible. This field ordinarily includes the strength of the dosage form (in metric units), the units in which the dosage form is available for prescribing, appropriate information to facilitate identification of the dosage forms (such as shape, color, coating, scoring, and National Drug Code), and special handling and storage condition information.16 HOW SUPPLIED/STORAGE AND HANDLING 16.1 How Supplied Topiramate tablets, USP are available as debossed, film-coated, circular tablets in the following strengths and colors: 25 mg white (coded S on one side; 707 on the other) They are supplied as follows: 25 mg tablets Bottles of 30 NDC 68071-3012-3 Bottles of 60 NDC 68071-3012-6 Bottles of 90 NDC 68071-3012-9 16.2 Storage and Handling Store topiramate tablets at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) [See USP Controlled Room Temperature]. Protect from moisture. Dispense in a tight container.
Disclaimer: Do not rely on openFDA or Phanrmacy Near Me to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated. Source: OpenFDA, Healthporta Drugs API