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Timolol maleate - Medication Information

Product NDC Code 0378-0055
Drug Name

Timolol maleate

Type Generic
Pharm Class Adrenergic beta-Antagonists [MoA],
beta-Adrenergic Blocker [EPC]
Active Ingredients
Timolol maleate 5 mg/1
Route ORAL
Dosage Form TABLET
RxCUI drug identifier 198284,
198285,
198286
Application Number ANDA072668
Labeler Name Mylan Pharmaceuticals Inc.
Packages
Package NDC Code Description
0378-0055-01 100 tablet in 1 bottle, plastic (0378-0055-01)
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Overdosage of timolol maleate

Information about signs, symptoms, and laboratory findings of acute ovedosage and the general principles of overdose treatment.
OVERDOSAGE Overdosage has been reported with timolol maleate tablets. A 30 year old female ingested 650 mg of timolol maleate (maximum recommended daily dose - 60 mg) and experienced second- and third-degree heart block. She recovered without treatment but approximately 2 months later developed irregular heart beat, hypertension, dizziness, tinnitus, faintness, increased pulse rate and borderline first degree heart block. The oral LD 50 of the drug is 1190 and 900 mg/kg in female mice and female rats, respectively. An in vitro hemodialysis study, using 14 C timolol added to human plasma or whole blood, showed that timolol was readily dialyzed from these fluids; however, a study of patients with renal failure showed that timolol did not dialyze readily. The most common signs and symptoms to be expected with overdosage with a beta-adrenergic receptor blocking agent are symptomatic bradycardia, hypotension, bronchospasm, and acute cardiac failure. Therapy with timolol should be discontinued and the patient observed closely. The following additional therapeutic measures should be considered: (1) Gastric lavage. (2) Symptomatic bradycardia: Use atropine sulfate intravenously in a dosage of 0.25 mg to 2 mg to induce vagal blockade. If bradycardia persists, intravenous isoproterenol hydrochloride should be administered cautiously. In refractory cases the use of a transvenous cardiac pacemaker may be considered. (3) Hypotension: Use sympathomimetic pressor drug therapy, such as dopamine, dobutamine or norepinephrine. In refractory cases the use of glucagon hydrochloride has been reported to be useful. (4) Bronchospasm: Use isoproterenol hydrochloride. Additional therapy with aminophylline may be considered. (5) Acute cardiac failure: Conventional therapy with digitalis, diuretics, and oxygen should be instituted immediately. In refractory cases the use of intravenous aminophylline is suggested. This may be followed if necessary by glucagon hydrochloride which has been reported to be useful. (6) Heart block (second- or third-degree): Use isoproterenol hydrochloride or a transvenous cardiac pacemaker.

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.
ADVERSE REACTIONS Timolol maleate tablets are usually well tolerated in properly selected patients. Most adverse effects have been mild and transient. In a multi-center (12 week) clinical trial comparing timolol maleate and placebo in hypertensive patients, the following adverse reactions were reported spontaneously and considered to be causally related to timolol maleate: Timolol Maleate (n=176) % Placebo (n=168) % BODY AS A WHOLE fatigue/tiredness 3.4 0.6 headache 1.7 1.8 chest pain 0.6 0 asthenia 0.6 0 CARDIOVASCULAR bradycardia 9.1 0 arrhythmia 1.1 0.6 syncope 0.6 0 edema 0.6 1.2 DIGESTIVE dyspepsia 0.6 0.6 nausea 0.6 0 SKIN pruritus 1.1 0 NERVOUS SYSTEM dizziness 2.3 1.2 vertigo 0.6 0 paresthesia 0.6 0 PSYCHIATRIC decreased libido 0.6 0 RESPIRATORY dyspnea 1.7 0.6 bronchial spasm 0.6 0 rales 0.6 0 SPECIAL SENSES eye irritation 1.1 0.6 tinnitus 0.6 0 These data are representative of the incidence of adverse effects that may be observed in properly selected patients treated with timolol maleate, i.e., excluding patients with bronchospastic disease, congestive heart failure or other contraindications to beta-blocker therapy. In patients with migraine the incidence of bradycardia was 5 percent. In a coronary artery disease population studied in the Norwegian multi-center trial (see CLINICAL PHARMACOLOGY ), the frequency of the principal adverse reactions and the frequency with which these resulted in discontinuation of therapy in the timolol and placebo groups were: Adverse Reaction When an adverse reaction recurred in a patient, it is listed only once. Withdrawal Only principal reason for withdrawal in each patient is listed. These adverse reactions can also occur in patients treated for hypertension. Timolol Placebo Timolol Placebo (n=945) (n=939) (n=945) (n=939) % % % % Asthenia or Fatigue 5 1 <1 <1 Heart Rate < 40 beats/minute 5 <1 4 <1 Cardiac Failure-Nonfatal 8 7 3 2 Hypotension 3 2 3 1 Pulmonary Edema-Nonfatal 2 <1 <1 <1 Claudication 3 3 1 <1 AV Block 2nd or 3rd Degree <1 <1 <1 <1 Sinoatrial Block <1 <1 <1 <1 Cold Hands and Feet 8 <1 <1 0 Nausea or Digestive Disorders 8 6 1 <1 Dizziness 6 4 1 0 Bronchial Obstruction 2 <1 1 <1 The following additional adverse effects have been reported in clinical experience with the drug: Body as a Whole: anaphylaxis, extremity pain, decreased exercise tolerance, weight loss, fever; Cardiovascular: cardiac arrest, cardiac failure, cerebral vascular accident, worsening of angina pectoris, worsening of arterial insufficiency, Raynaud’s phenomenon, palpitations, vasodilatation; Digestive: gastrointestinal pain, hepatomegaly, vomiting, diarrhea, dyspepsia; Hematologic: nonthrombocytopenic purpura; Endocrine: hyperglycemia, hypoglycemia; Skin: rash, skin irritation, increased pigmentation, sweating, alopecia; Musculoskeletal: arthralgia; Nervous System: local weakness, increase in signs and symptoms of myasthenia gravis; Psychiatric: depression, nightmares, somnolence, insomnia, nervousness, diminished concentration, hallucinations; Respiratory: cough; Special Senses: visual disturbances, diplopia, ptosis, dry eyes; Urogenital: impotence, urination difficulties. There have been reports of retroperitoneal fibrosis in patients receiving timolol maleate and in patients receiving other beta-adrenergic blocking agents. A causal relationship between this condition and therapy with beta-adrenergic blocking agents has not been established. Potential Adverse Effects In addition, a variety of adverse effects not observed in clinical trials with timolol maleate, but reported with other beta-adrenergic blocking agents, should be considered potential adverse effects of timolol. Nervous System: Reversible mental depression progressing to catatonia; an acute reversible syndrome characterized by disorientation for time and place, short-term memory loss, emotional lability, slightly clouded sensorium, and decreased performance on neuropsychometrics; Cardiovascular: Intensification of AV block (see CONTRAINDICATIONS ); Digestive: Mesenteric arterial thrombosis, ischemic colitis; Hematologic: Agranulocytosis, thrombocytopenic purpura; Allergic: Erythematous rash, fever combined with aching and sore throat, laryngospasm with respiratory distress; Miscellaneous: Peyronie’s disease. There have been reports of a syndrome comprising psoriasiform skin rash, conjunctivitis sicca, otitis, and sclerosing serositis attributed to the beta-adrenergic receptor blocking agent, practolol. This syndrome has not been reported with timolol. Clinical Laboratory Test Findings Clinically important changes in standard laboratory parameters were rarely associated with the administration of timolol. Slight increases in blood urea nitrogen, serum potassium, uric acid, and triglycerides, and slight decreases in hemoglobin, hematocrit and HDL cholesterol occurred, but were not progressive or associated with clinical manifestations. Increases in liver function tests have been reported.
Timolol Maleate (n=176) %Placebo (n=168) %
BODY AS A WHOLE
fatigue/tiredness3.40.6
headache1.71.8
chest pain0.60
asthenia0.60
CARDIOVASCULAR
bradycardia9.10
arrhythmia1.10.6
syncope0.60
edema0.61.2
DIGESTIVE
dyspepsia0.60.6
nausea0.60
SKIN
pruritus1.10
NERVOUS SYSTEM
dizziness2.31.2
vertigo0.60
paresthesia0.60
PSYCHIATRIC
decreased libido0.60
RESPIRATORY
dyspnea1.70.6
bronchial spasm0.60
rales0.60
SPECIAL SENSES
eye irritation1.10.6
tinnitus0.60
Adverse ReactionWhen an adverse reaction recurred in a patient, it is listed only once.WithdrawalOnly principal reason for withdrawal in each patient is listed. These adverse reactions can also occur in patients treated for hypertension.
TimololPlaceboTimololPlacebo
(n=945)(n=939)(n=945)(n=939)
%%%%
Asthenia or Fatigue51<1<1
Heart Rate < 40 beats/minute5<14<1
Cardiac Failure-Nonfatal8732
Hypotension3231
Pulmonary Edema-Nonfatal2<1<1<1
Claudication331<1
AV Block 2nd or 3rd Degree<1<1<1<1
Sinoatrial Block<1<1<1<1
Cold Hands and Feet8<1<10
Nausea or Digestive Disorders861<1
Dizziness6410
Bronchial Obstruction2<11<1

timolol maleate 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.
Drug Interactions Catecholamine-Depleting Drugs Close observation of the patient is recommended when timolol is administered to patients receiving catecholamine-depleting drugs such as reserpine, because of possible additive effects and the production of hypotension and/or marked bradycardia, which may produce vertigo, syncope, or postural hypotension. Non-Steroidal Anti-Inflammatory Drugs Blunting of the antihypertensive effect of beta-adrenoceptor blocking agents by non-steroidal anti-inflammatory drugs has been reported. When using these agents concomitantly, patients should be observed carefully to confirm that the desired therapeutic effect has been obtained. Calcium Antagonists Literature reports suggest that oral calcium antagonists may be used in combination with beta-adrenergic blocking agents when heart function is normal, but should be avoided in patients with impaired cardiac function. Hypotension, AV conduction disturbances, and left ventricular failure have been reported in some patients receiving beta-adrenergic blocking agents when an oral calcium antagonist was added to the treatment regimen. Hypotension was more likely to occur if the calcium antagonist were a dihydropyridine derivative, e.g., nifedipine, while left ventricular failure and AV conduction disturbances were more likely to occur with either verapamil or diltiazem. Intravenous calcium antagonists should be used with caution in patients receiving beta-adrenergic blocking agents. Digitalis and Either Diltiazem or Verapamil The concomitant use of beta-adrenergic blocking agents with digitalis and either diltiazem or verapamil may have additive effects in prolonging AV conduction time. Quinidine Potentiated systemic beta-blockade (e.g., decreased heart rate) has been reported during combined treatment with quinidine and timolol, possibly because quinidine inhibits the metabolism of timolol via the P-450 enzyme, CYP2D6. Clonidine Beta-adrenergic blocking agents may exacerbate the rebound hypertension which can follow the withdrawal of clonidine. If the two drugs are coadministered, the beta-adrenergic blocking agent should be withdrawn several days before the gradual withdrawal of clonidine. If replacing clonidine by beta-blocker therapy, the introduction of beta-adrenergic blocking agents should be delayed for several days after clonidine administration has stopped.

Clinical pharmacology

Information about the clinical pharmacology and actions of the drug in humans.
CLINICAL PHARMACOLOGY Timolol maleate is a beta 1 and beta 2 (nonselective) adrenergic receptor blocking agent that does not have significant intrinsic sympathomimetic, direct myocardial depressant, or local anesthetic activity. Pharmacodynamics Clinical pharmacology studies have confirmed the beta-adrenergic blocking activity as shown by (1) changes in resting heart rate and response of heart rate to changes in posture; (2) inhibition of isoproterenol-induced tachycardia; (3) alteration of the response to the Valsalva maneuver and amyl nitrite administration; and (4) reduction of heart rate and blood pressure changes on exercise. Timolol decreases the positive chronotropic, positive inotropic, bronchodilator, and vasodilator responses caused by beta-adrenergic receptor agonists. The magnitude of this decreased response is proportional to the existing sympathetic tone and the concentration of timolol at receptor sites. In normal volunteers, the reduction in heart rate response to a standard exercise was dose dependent over the test range of 0.5 to 20 mg, with a peak reduction at 2 hours of approximately 30% at higher doses. Beta-adrenergic receptor blockade reduces cardiac output in both healthy subjects and patients with heart disease. In patients with severe impairment of myocardial function beta-adrenergic receptor blockade may inhibit the stimulatory effect of the sympathetic nervous system necessary to maintain adequate cardiac function. Beta-adrenergic receptor blockade in the bronchi and bronchioles results in increased airway resistance from unopposed parasympathetic activity. Such an effect in patients with asthma or other bronchospastic conditions is potentially dangerous. Clinical studies indicate that timolol maleate at a dosage of 20 to 60 mg/day reduces blood pressure without causing postural hypotension in most patients with essential hypertension. Administration of timolol to patients with hypertension results initially in a decrease in cardiac output, little immediate change in blood pressure, and an increase in calculated peripheral resistance. With continued administration of timolol, blood pressure decreases within a few days, cardiac output usually remains reduced, and peripheral resistance falls toward pretreatment levels. Plasma volume may decrease or remain unchanged during therapy with timolol. In the majority of patients with hypertension timolol also decreases plasma renin activity. Dosage adjustment to achieve optimal antihypertensive effect may require a few weeks. When therapy with timolol is discontinued, the blood pressure tends to return to pretreatment levels gradually. In most patients the antihypertensive activity of timolol is maintained with long-term therapy and is well tolerated. The mechanism of the antihypertensive effects of beta-adrenergic receptor blocking agents is not established at this time. Possible mechanisms of action include reduction in cardiac output, reduction in plasma renin activity, and a central nervous system sympatholytic action. A Norwegian multi-center, double-blind study, which included patients 20 to 75 years of age, compared the effects of timolol maleate with placebo in 1,884 patients who had survived the acute phase of a myocardial infarction. Patients with systolic blood pressure below 100 mm Hg, sick sinus syndrome and contraindications to beta-blockers, including uncontrolled heart failure, second- or third-degree AV block and bradycardia (< 50 beats per minute), were excluded from the multi-center trial. Therapy with timolol, begun 7 to 28 days following infarction, was shown to reduce overall mortality; this was primarily attributable to a reduction in cardiovascular mortality. Timolol significantly reduced the incidence of sudden deaths (deaths occurring without symptoms or within 24 hours of the onset of symptoms), including those occurring within one hour, and particularly instantaneous deaths (those occurring without preceding symptoms). The protective effect of timolol was consistent regardless of age, sex or site of infarction. The effect was clearest in patients with a first infarction who were considered at a high risk of dying, defined as those with one or more of the following characteristics during the acute phase: transient left ventricular failure, cardiomegaly, newly appearing atrial fibrillation or flutter, systolic hypotension, or SGOT (ASAT) levels greater than four times the upper limit of normal. Therapy with timolol also reduced the incidence of nonfatal reinfarction. The mechanism of the protective effect of timolol is unknown. Timolol was studied for the prophylactic treatment of migraine headache in placebo-controlled clinical trials involving 400 patients, mostly women between the ages of 18 and 66 years. Common migraine was the most frequent diagnosis. All patients had at least two headaches per month at baseline. Approximately 50 percent of patients who received timolol had a reduction in the frequency of migraine headache of at least 50 percent, compared to a similar decrease in frequency in 30 percent of patients receiving placebo. The most common cardiovascular adverse effect was bradycardia (5%). Pharmacokinetics and Metabolism Timolol maleate is rapidly and nearly completely absorbed (about 90%) following oral ingestion. Detectable plasma levels of timolol occur within one-half hour and peak plasma levels occur in about one to two hours. The drug half-life in plasma is approximately 4 hours and this is essentially unchanged in patients with moderate renal insufficiency. Timolol is partially metabolized by the liver and timolol and its metabolites are excreted by the kidney. Timolol is not extensively bound to plasma proteins; i.e., < 10% by equilibrium dialysis and approximately 60% by ultrafiltration. An in vitro hemodialysis study, using 14 C timolol added to human plasma or whole blood, showed that timolol was readily dialyzed from these fluids; however, a study of patients with renal failure showed that timolol did not dialyze readily. Plasma levels following oral administration are about half those following intravenous administration indicating approximately 50% first pass metabolism. The level of beta sympathetic activity varies widely among individuals, and no simple correlation exists between the dose or plasma level of timolol maleate and its therapeutic activity. Therefore, objective clinical measurements such as reduction of heart rate and/or blood pressure should be used as guides in determining the optimal dosage for each patient.

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.
Pharmacodynamics Clinical pharmacology studies have confirmed the beta-adrenergic blocking activity as shown by (1) changes in resting heart rate and response of heart rate to changes in posture; (2) inhibition of isoproterenol-induced tachycardia; (3) alteration of the response to the Valsalva maneuver and amyl nitrite administration; and (4) reduction of heart rate and blood pressure changes on exercise. Timolol decreases the positive chronotropic, positive inotropic, bronchodilator, and vasodilator responses caused by beta-adrenergic receptor agonists. The magnitude of this decreased response is proportional to the existing sympathetic tone and the concentration of timolol at receptor sites. In normal volunteers, the reduction in heart rate response to a standard exercise was dose dependent over the test range of 0.5 to 20 mg, with a peak reduction at 2 hours of approximately 30% at higher doses. Beta-adrenergic receptor blockade reduces cardiac output in both healthy subjects and patients with heart disease. In patients with severe impairment of myocardial function beta-adrenergic receptor blockade may inhibit the stimulatory effect of the sympathetic nervous system necessary to maintain adequate cardiac function. Beta-adrenergic receptor blockade in the bronchi and bronchioles results in increased airway resistance from unopposed parasympathetic activity. Such an effect in patients with asthma or other bronchospastic conditions is potentially dangerous. Clinical studies indicate that timolol maleate at a dosage of 20 to 60 mg/day reduces blood pressure without causing postural hypotension in most patients with essential hypertension. Administration of timolol to patients with hypertension results initially in a decrease in cardiac output, little immediate change in blood pressure, and an increase in calculated peripheral resistance. With continued administration of timolol, blood pressure decreases within a few days, cardiac output usually remains reduced, and peripheral resistance falls toward pretreatment levels. Plasma volume may decrease or remain unchanged during therapy with timolol. In the majority of patients with hypertension timolol also decreases plasma renin activity. Dosage adjustment to achieve optimal antihypertensive effect may require a few weeks. When therapy with timolol is discontinued, the blood pressure tends to return to pretreatment levels gradually. In most patients the antihypertensive activity of timolol is maintained with long-term therapy and is well tolerated. The mechanism of the antihypertensive effects of beta-adrenergic receptor blocking agents is not established at this time. Possible mechanisms of action include reduction in cardiac output, reduction in plasma renin activity, and a central nervous system sympatholytic action. A Norwegian multi-center, double-blind study, which included patients 20 to 75 years of age, compared the effects of timolol maleate with placebo in 1,884 patients who had survived the acute phase of a myocardial infarction. Patients with systolic blood pressure below 100 mm Hg, sick sinus syndrome and contraindications to beta-blockers, including uncontrolled heart failure, second- or third-degree AV block and bradycardia (< 50 beats per minute), were excluded from the multi-center trial. Therapy with timolol, begun 7 to 28 days following infarction, was shown to reduce overall mortality; this was primarily attributable to a reduction in cardiovascular mortality. Timolol significantly reduced the incidence of sudden deaths (deaths occurring without symptoms or within 24 hours of the onset of symptoms), including those occurring within one hour, and particularly instantaneous deaths (those occurring without preceding symptoms). The protective effect of timolol was consistent regardless of age, sex or site of infarction. The effect was clearest in patients with a first infarction who were considered at a high risk of dying, defined as those with one or more of the following characteristics during the acute phase: transient left ventricular failure, cardiomegaly, newly appearing atrial fibrillation or flutter, systolic hypotension, or SGOT (ASAT) levels greater than four times the upper limit of normal. Therapy with timolol also reduced the incidence of nonfatal reinfarction. The mechanism of the protective effect of timolol is unknown. Timolol was studied for the prophylactic treatment of migraine headache in placebo-controlled clinical trials involving 400 patients, mostly women between the ages of 18 and 66 years. Common migraine was the most frequent diagnosis. All patients had at least two headaches per month at baseline. Approximately 50 percent of patients who received timolol had a reduction in the frequency of migraine headache of at least 50 percent, compared to a similar decrease in frequency in 30 percent of patients receiving placebo. The most common cardiovascular adverse effect was bradycardia (5%).

Pharmacokinetics

Information about the clinically significant pharmacokinetics of a drug or active metabolites, for instance pertinent absorption, distribution, metabolism, and excretion parameters.
Pharmacokinetics and Metabolism Timolol maleate is rapidly and nearly completely absorbed (about 90%) following oral ingestion. Detectable plasma levels of timolol occur within one-half hour and peak plasma levels occur in about one to two hours. The drug half-life in plasma is approximately 4 hours and this is essentially unchanged in patients with moderate renal insufficiency. Timolol is partially metabolized by the liver and timolol and its metabolites are excreted by the kidney. Timolol is not extensively bound to plasma proteins; i.e., < 10% by equilibrium dialysis and approximately 60% by ultrafiltration. An in vitro hemodialysis study, using 14 C timolol added to human plasma or whole blood, showed that timolol was readily dialyzed from these fluids; however, a study of patients with renal failure showed that timolol did not dialyze readily. Plasma levels following oral administration are about half those following intravenous administration indicating approximately 50% first pass metabolism. The level of beta sympathetic activity varies widely among individuals, and no simple correlation exists between the dose or plasma level of timolol maleate and its therapeutic activity. Therefore, objective clinical measurements such as reduction of heart rate and/or blood pressure should be used as guides in determining the optimal dosage for each patient.

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.
CONTRAINDICATIONS Timolol maleate is contraindicated in patients with bronchial asthma or with a history of bronchial asthma, or severe chronic obstructive pulmonary disease (see WARNINGS ); sinus bradycardia; second- and third-degree atrioventricular block; overt cardiac failure (see WARNINGS ); cardiogenic shock; hypersensitivity to this product.

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.
DESCRIPTION Timolol maleate is a nonselective beta-adrenergic receptor blocking agent. The chemical name for timolol maleate is ( S )-1-[(1,1-dimethylethyl)amino]-3-[[4-(4-morpholinyl)-1,2,5-thiadiazol-3-yl]oxy]-2-propanol ( Z )-2-butenedioate (1:1) salt. It possesses an asymmetric carbon atom in its structure and is provided as the levo isomer. Its molecular formula is C 13 H 24 N 4 O 3 S•C 4 H 4 O 4 and its structural formula is: Timolol maleate has a molecular weight of 432.50. It is a white, odorless, crystalline powder which is soluble in water, methanol, and alcohol. Timolol maleate is supplied as tablets containing 5 mg, 10 mg and 20 mg timolol maleate for oral administration. Inactive ingredients are: colloidal silicon dioxide, croscarmellose sodium, magnesium stearate, microcrystalline cellulose, pregelatinized starch (corn), sodium lauryl sulfate, FD&C Blue No. 2 aluminum lake, and D&C Yellow No. 10 aluminum lake. Timolol Maleate Structural Formula

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.
DOSAGE AND ADMINISTRATION Hypertension The usual initial dosage of timolol maleate is 10 mg twice a day, whether used alone or added to diuretic therapy. Dosage may be increased or decreased depending on heart rate and blood pressure response. The usual total maintenance dosage is 20 to 40 mg per day. Increases in dosage to a maximum of 60 mg per day divided into two doses may be necessary. There should be an interval of at least 7 days between increases in dosages. Timolol maleate tablets may be used with a thiazide diuretic or with other antihypertensive agents. Patients should be observed carefully during initiation of such concomitant therapy. Myocardial Infarction The recommended dosage for long-term prophylactic use in patients who have survived the acute phase of a myocardial infarction is 10 mg given twice daily (see CLINICAL PHARMACOLOGY ). Migraine The usual initial dosage of timolol maleate is 10 mg twice a day. During maintenance therapy the 20 mg daily dosage may be administered as a single dose. Total daily dosage may be increased to a maximum of 30 mg, given in divided doses, or decreased to 10 mg once per day, depending on clinical response and tolerability. If a satisfactory response is not obtained after 6 to 8 weeks use of the maximum daily dosage, therapy with timolol should be discontinued.

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.
INDICATIONS AND USAGE Hypertension Timolol maleate tablets are indicated for the treatment of hypertension. They may be used alone or in combination with other antihypertensive agents, especially thiazide-type diuretics. Myocardial Infarction Timolol is indicated in patients who have survived the acute phase of myocardial infarction, and are clinically stable, to reduce cardiovascular mortality and the risk of reinfarction. Migraine Timolol is indicated for the prophylaxis of migraine headache.

Spl product data elements

Usually a list of ingredients in a drug product.
Timolol Maleate timolol maleate TIMOLOL MALEATE TIMOLOL ANHYDROUS SILICON DIOXIDE CROSCARMELLOSE SODIUM MAGNESIUM STEARATE MICROCRYSTALLINE CELLULOSE STARCH, CORN SODIUM LAURYL SULFATE FD&C BLUE NO. 2 D&C YELLOW NO. 10 M;55 Timolol Maleate timolol maleate TIMOLOL MALEATE TIMOLOL ANHYDROUS SILICON DIOXIDE CROSCARMELLOSE SODIUM MAGNESIUM STEARATE MICROCRYSTALLINE CELLULOSE STARCH, CORN SODIUM LAURYL SULFATE FD&C BLUE NO. 2 D&C YELLOW NO. 10 M;221 Timolol Maleate timolol maleate TIMOLOL MALEATE TIMOLOL ANHYDROUS SILICON DIOXIDE CROSCARMELLOSE SODIUM MAGNESIUM STEARATE MICROCRYSTALLINE CELLULOSE STARCH, CORN SODIUM LAURYL SULFATE FD&C BLUE NO. 2 D&C YELLOW NO. 10 capsule-shaped M;715

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.
Carcinogenesis, Mutagenesis, Impairment of Fertility In a 2 year study of timolol maleate in rats, there was a statistically significant increase in the incidence of adrenal pheochromocytomas in male rats administered 300 mg/kg/day (250 times * the maximum recommended human dose). Similar differences were not observed in rats administered doses equivalent to approximately 20 or 80 times * the maximum recommended human dose. In a lifetime study in mice, there were statistically significant increases in the incidence of benign and malignant pulmonary tumors, benign uterine polyps and mammary adenocarcinoma in female mice at 500 mg/kg/day (approximately 400 times * the maximum recommended human dose), but not at a 5 or 50 mg/kg/day. In a subsequent study in female mice, in which postmortem examinations were limited to uterus and lungs, a statistically significant increase in the incidence of pulmonary tumors was again observed at 500 mg/kg/day. The increased occurrence of mammary adenocarcinoma was associated with elevations in serum prolactin that occurred in female mice administered timolol maleate at 500 mg/kg/day, but not at doses of 5 or 50 mg/kg/day. An increased incidence of mammary adenocarcinomas in rodents has been associated with administration of several other therapeutic agents which elevate serum prolactin, but no correlation between serum prolactin levels and mammary tumors has been established in man. Furthermore, in adult human female subjects who received oral dosages of up to 60 mg of timolol maleate, the maximum recommended daily human oral dosage, there were no clinically meaningful changes in serum prolactin. Timolol maleate was devoid of mutagenic potential when elevated in vivo (mouse) in the micronucleus test and cytogenetic assay (doses up to 800 mg/kg) and in vitro in a neoplastic cell transformation assay (up to 100 mcg/mL). In Ames tests the highest concentrations of timolol employed, 5,000 or 10,000 mcg/plate, were associated with statistically significant elevations of revertants observed with tester strain TA100 (in seven replicate assays), but not in three additional strains. In the assays with tester strain TA100, no consistent dose-response relationship was observed, nor did the ratio of test to control revertants reach 2. A ratio of 2 is usually considered the criterion for a positive Ames test. Reproduction and fertility studies in rats showed no adverse effect on male or female fertility at doses up to 125 times * the maximum recommended human dose.

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 - 5 mg NDC 0378-0055-01 Timolol Maleate Tablets, USP 5 mg Rx only 100 Tablets Each tablet contains: Timolol maleate, USP 5 mg Usual Dosage: See accompanying prescribing information. Keep this and all medication out of the reach of children. Store at 20° to 25°C (68° to 77°F). [See USP Controlled Room Temperature.] Protect from light. Manufactured for: Mylan Pharmaceuticals Inc. Morgantown, WV 26505 U.S.A. Made in India Mylan.com RMXI0055A Dispense in a tight, light-resistant container as defined in the USP using a child-resistant closure. Keep container tightly closed. Code No.: MP/DRUGS/25/1/2014 Timolol Maleate Tablets 5 mg Bottle Label PRINCIPAL DISPLAY PANEL - 10 mg NDC 0378-0221-01 Timolol Maleate Tablets, USP 10 mg Rx only 100 Tablets Each tablet contains: Timolol maleate, USP 10 mg Usual Dosage: See accompanying prescribing information. Keep this and all medication out of the reach of children. Store at 20° to 25°C (68° to 77°F). [See USP Controlled Room Temperature.] Protect from light. Manufactured for: Mylan Pharmaceuticals Inc. Morgantown, WV 26505 U.S.A. Made in India Mylan.com RMXI0221A Dispense in a tight, light-resistant container as defined in the USP using a child-resistant closure. Keep container tightly closed. Code No.: MP/DRUGS/25/1/2014 Timolol Maleate Tablets 10 mg Bottle Label PRINCIPAL DISPLAY PANEL - 20 mg NDC 0378-0715-01 Timolol Maleate Tablets, USP 20 mg Rx only 100 Tablets Each tablet contains: Timolol maleate, USP 20 mg Usual Dosage: See accompanying prescribing information. Keep this and all medication out of the reach of children. Store at 20° to 25°C (68° to 77°F). [See USP Controlled Room Temperature.] Protect from light. Manufactured for: Mylan Pharmaceuticals Inc. Morgantown, WV 26505 U.S.A. Made in India Mylan.com RMXI0715A Dispense in a tight, light-resistant container as defined in the USP using a child-resistant closure. Keep container tightly closed. Code No.: MP/DRUGS/25/1/2014 Timolol Maleate Tablets 20 mg Bottle Label

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.
Geriatric Use Clinical studies of timolol for the treatment of hypertension or migraine did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In a clinical study of timolol in patients who had survived the acute phase of a myocardial infarction, approximately 350 patients (37%) were 65 to 75 years of age. Safety and efficacy were not different between these patients and younger patients (see CLINICAL PHARMACOLOGY: Pharmacodynamics ). Other reported clinical experience has not identified differences in response between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy. This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function. (See PRECAUTIONS: Impaired Hepatic or Renal Function and Dosing in the Presence of Marked Renal Failure .) The results from 5 single- and/or multiple-dose PK studies comparing the impact of age on the PK of hydrochlorothiazide, when given in combination with other antihypertensive drugs, were consistent. They indicated a mean median increase in C max and AUC of 38% and 99% respectively, in elderly relative to younger subjects. * Based on patient weight of 50 kg.

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.
Nursing Mothers Timolol maleate has been detected in human milk. Because of the potential for serious adverse reactions from timolol in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

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.
Pediatric Use Safety and effectiveness in pediatric patients have not been established.

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.)
Pregnancy Teratogenic Effects Teratogenicity studies with timolol in mice, rats and rabbits at doses up to 50 mg/kg/day (approximately 40 times * the maximum recommended daily human dose) showed no evidence of fetal malformations. Although delayed fetal ossification was observed at this dose in rats, there were no adverse effects on postnatal development of offspring. Doses of 1000 mg/kg/day (approximately 830 times * the maximum recommended daily human dose) were maternotoxic in mice and resulted in an increased number of fetal resorptions. Increased fetal resorptions were also seen in rabbits at doses of approximately 40 times * the maximum recommended daily human dose, in this case without apparent maternotoxicity. There are no adequate and well controlled studies in pregnant women. Timolol should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Teratogenic effects

Pregnancy category A: Adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the fetus in the first trimester of pregnancy, and there is no evidence of a risk in later trimesters. Pregnancy category B: Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women. Pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus, there are no adequate and well-controlled studies in humans, and the benefits from the use of the drug in pregnant women may be acceptable despite its potential risks. Pregnancy category D: There is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but the potential benefits from the use of the drug in pregnant women may be acceptable despite its potential risks (for example, if the drug is needed in a life-threatening situation or serious disease for which safer drugs cannot be used or are ineffective). Pregnancy category X: Studies in animals or humans have demonstrated fetal abnormalities or there is positive evidence of fetal risk based on adverse reaction reports from investigational or marketing experience, or both, and the risk of the use of the drug in a pregnant woman clearly outweighs any possible benefit (for example, safer drugs or other forms of therapy are available).
Teratogenic Effects Teratogenicity studies with timolol in mice, rats and rabbits at doses up to 50 mg/kg/day (approximately 40 times * the maximum recommended daily human dose) showed no evidence of fetal malformations. Although delayed fetal ossification was observed at this dose in rats, there were no adverse effects on postnatal development of offspring. Doses of 1000 mg/kg/day (approximately 830 times * the maximum recommended daily human dose) were maternotoxic in mice and resulted in an increased number of fetal resorptions. Increased fetal resorptions were also seen in rabbits at doses of approximately 40 times * the maximum recommended daily human dose, in this case without apparent maternotoxicity. There are no adequate and well controlled studies in pregnant women. Timolol should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

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.
HOW SUPPLIED Timolol Maleate Tablets, USP are available containing 5 mg, 10 mg and 20 mg of timolol maleate, USP. The 5 mg tablets are green, round, flat-faced, unscored tablets debossed with M over 55 on one side of the tablet and blank on the other side. They are available as follows: NDC 0378-0055-01 bottles of 100 tablets The 10 mg tablets are green, round, flat-faced, scored tablets debossed with M above the score and 221 below the score on one side of the tablet and blank on the other side. They are available as follows: NDC 0378-0221-01 bottles of 100 tablets The 20 mg tablets are green, capsule-shaped, scored tablets debossed with M to the left of the score and 715 to the right of the score on one side of the tablet and blank on the other side. They are available as follows: NDC 0378-0715-01 bottles of 100 tablets Store at 20° to 25°C (68° to 77°F). [See USP Controlled Room Temperature.] Protect from light. Dispense in a tight, light-resistant container as defined in the USP using a child-resistant closure. Mylan Pharmaceuticals Inc. Morgantown, WV 26505 Revised: 7/2020 TIM:R16

General precautions

Information about any special care to be exercised for safe and effective use of the drug.
General Impaired Hepatic or Renal Function Since timolol is partially metabolized in the liver and excreted mainly by the kidneys, dosage reductions may be necessary when hepatic and/or renal insufficiency is present. Dosing in the Presence of Marked Renal Failure Although the pharmacokinetics of timolol are not greatly altered by renal impairment, marked hypotensive responses have been seen in patients with marked renal impairment undergoing dialysis after 20 mg doses. Dosing in such patients should therefore be especially cautious. Muscle Weakness Beta-adrenergic blockade has been reported to potentiate muscle weakness consistent with certain myasthenic symptoms (e.g., diplopia, ptosis, and generalized weakness). Timolol has been reported rarely to increase muscle weakness in some patients with myasthenia gravis or myasthenic symptoms. Cerebrovascular Insufficiency Because of potential effects of beta-adrenergic blocking agents relative to blood pressure and pulse, these agents should be used with caution in patients with cerebrovascular insufficiency. If signs or symptoms suggesting reduced cerebral blood flow are observed, consideration should be given to discontinuing these agents.

Precautions

Information about any special care to be exercised for safe and effective use of the drug.
PRECAUTIONS General Impaired Hepatic or Renal Function Since timolol is partially metabolized in the liver and excreted mainly by the kidneys, dosage reductions may be necessary when hepatic and/or renal insufficiency is present. Dosing in the Presence of Marked Renal Failure Although the pharmacokinetics of timolol are not greatly altered by renal impairment, marked hypotensive responses have been seen in patients with marked renal impairment undergoing dialysis after 20 mg doses. Dosing in such patients should therefore be especially cautious. Muscle Weakness Beta-adrenergic blockade has been reported to potentiate muscle weakness consistent with certain myasthenic symptoms (e.g., diplopia, ptosis, and generalized weakness). Timolol has been reported rarely to increase muscle weakness in some patients with myasthenia gravis or myasthenic symptoms. Cerebrovascular Insufficiency Because of potential effects of beta-adrenergic blocking agents relative to blood pressure and pulse, these agents should be used with caution in patients with cerebrovascular insufficiency. If signs or symptoms suggesting reduced cerebral blood flow are observed, consideration should be given to discontinuing these agents. Drug Interactions Catecholamine-Depleting Drugs Close observation of the patient is recommended when timolol is administered to patients receiving catecholamine-depleting drugs such as reserpine, because of possible additive effects and the production of hypotension and/or marked bradycardia, which may produce vertigo, syncope, or postural hypotension. Non-Steroidal Anti-Inflammatory Drugs Blunting of the antihypertensive effect of beta-adrenoceptor blocking agents by non-steroidal anti-inflammatory drugs has been reported. When using these agents concomitantly, patients should be observed carefully to confirm that the desired therapeutic effect has been obtained. Calcium Antagonists Literature reports suggest that oral calcium antagonists may be used in combination with beta-adrenergic blocking agents when heart function is normal, but should be avoided in patients with impaired cardiac function. Hypotension, AV conduction disturbances, and left ventricular failure have been reported in some patients receiving beta-adrenergic blocking agents when an oral calcium antagonist was added to the treatment regimen. Hypotension was more likely to occur if the calcium antagonist were a dihydropyridine derivative, e.g., nifedipine, while left ventricular failure and AV conduction disturbances were more likely to occur with either verapamil or diltiazem. Intravenous calcium antagonists should be used with caution in patients receiving beta-adrenergic blocking agents. Digitalis and Either Diltiazem or Verapamil The concomitant use of beta-adrenergic blocking agents with digitalis and either diltiazem or verapamil may have additive effects in prolonging AV conduction time. Quinidine Potentiated systemic beta-blockade (e.g., decreased heart rate) has been reported during combined treatment with quinidine and timolol, possibly because quinidine inhibits the metabolism of timolol via the P-450 enzyme, CYP2D6. Clonidine Beta-adrenergic blocking agents may exacerbate the rebound hypertension which can follow the withdrawal of clonidine. If the two drugs are coadministered, the beta-adrenergic blocking agent should be withdrawn several days before the gradual withdrawal of clonidine. If replacing clonidine by beta-blocker therapy, the introduction of beta-adrenergic blocking agents should be delayed for several days after clonidine administration has stopped. Risk of Anaphylactic Reaction While taking beta-blockers, patients with a history of atopy or a history of severe anaphylactic reaction to a variety of allergens may be more reactive to repeated accidental, diagnostic, or therapeutic challenge with such allergens. Such patients may be unresponsive to the usual doses of epinephrine used to treat anaphylactic reactions. Carcinogenesis, Mutagenesis, Impairment of Fertility In a 2 year study of timolol maleate in rats, there was a statistically significant increase in the incidence of adrenal pheochromocytomas in male rats administered 300 mg/kg/day (250 times * the maximum recommended human dose). Similar differences were not observed in rats administered doses equivalent to approximately 20 or 80 times * the maximum recommended human dose. In a lifetime study in mice, there were statistically significant increases in the incidence of benign and malignant pulmonary tumors, benign uterine polyps and mammary adenocarcinoma in female mice at 500 mg/kg/day (approximately 400 times * the maximum recommended human dose), but not at a 5 or 50 mg/kg/day. In a subsequent study in female mice, in which postmortem examinations were limited to uterus and lungs, a statistically significant increase in the incidence of pulmonary tumors was again observed at 500 mg/kg/day. The increased occurrence of mammary adenocarcinoma was associated with elevations in serum prolactin that occurred in female mice administered timolol maleate at 500 mg/kg/day, but not at doses of 5 or 50 mg/kg/day. An increased incidence of mammary adenocarcinomas in rodents has been associated with administration of several other therapeutic agents which elevate serum prolactin, but no correlation between serum prolactin levels and mammary tumors has been established in man. Furthermore, in adult human female subjects who received oral dosages of up to 60 mg of timolol maleate, the maximum recommended daily human oral dosage, there were no clinically meaningful changes in serum prolactin. Timolol maleate was devoid of mutagenic potential when elevated in vivo (mouse) in the micronucleus test and cytogenetic assay (doses up to 800 mg/kg) and in vitro in a neoplastic cell transformation assay (up to 100 mcg/mL). In Ames tests the highest concentrations of timolol employed, 5,000 or 10,000 mcg/plate, were associated with statistically significant elevations of revertants observed with tester strain TA100 (in seven replicate assays), but not in three additional strains. In the assays with tester strain TA100, no consistent dose-response relationship was observed, nor did the ratio of test to control revertants reach 2. A ratio of 2 is usually considered the criterion for a positive Ames test. Reproduction and fertility studies in rats showed no adverse effect on male or female fertility at doses up to 125 times * the maximum recommended human dose. Pregnancy Teratogenic Effects Teratogenicity studies with timolol in mice, rats and rabbits at doses up to 50 mg/kg/day (approximately 40 times * the maximum recommended daily human dose) showed no evidence of fetal malformations. Although delayed fetal ossification was observed at this dose in rats, there were no adverse effects on postnatal development of offspring. Doses of 1000 mg/kg/day (approximately 830 times * the maximum recommended daily human dose) were maternotoxic in mice and resulted in an increased number of fetal resorptions. Increased fetal resorptions were also seen in rabbits at doses of approximately 40 times * the maximum recommended daily human dose, in this case without apparent maternotoxicity. There are no adequate and well controlled studies in pregnant women. Timolol should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Nursing Mothers Timolol maleate has been detected in human milk. Because of the potential for serious adverse reactions from timolol in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. Pediatric Use Safety and effectiveness in pediatric patients have not been established. Geriatric Use Clinical studies of timolol for the treatment of hypertension or migraine did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In a clinical study of timolol in patients who had survived the acute phase of a myocardial infarction, approximately 350 patients (37%) were 65 to 75 years of age. Safety and efficacy were not different between these patients and younger patients (see CLINICAL PHARMACOLOGY: Pharmacodynamics ). Other reported clinical experience has not identified differences in response between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy. This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function. (See PRECAUTIONS: Impaired Hepatic or Renal Function and Dosing in the Presence of Marked Renal Failure .) The results from 5 single- and/or multiple-dose PK studies comparing the impact of age on the PK of hydrochlorothiazide, when given in combination with other antihypertensive drugs, were consistent. They indicated a mean median increase in C max and AUC of 38% and 99% respectively, in elderly relative to younger subjects. * Based on patient weight of 50 kg.

Warnings

Information about serious adverse reactions and potential safety hazards, including limitations in use imposed by those hazards and steps that should be taken if they occur.
WARNINGS Cardiac Failure Sympathetic stimulation may be essential for support of the circulation in individuals with diminished myocardial contractility, and its inhibition by beta-adrenergic receptor blockade may precipitate more severe failure. Although beta-blockers should be avoided in overt congestive heart failure, they can be used, if necessary, with caution in patients with a history of failure who are well compensated, usually with digitalis and diuretics. Both digitalis and timolol maleate slow AV conduction. If cardiac failure persists, therapy with timolol maleate should be withdrawn. In Patients Without a History of Cardiac Failure Continued depression of the myocardium with beta-blocking agents over a period of time can, in some cases, lead to cardiac failure. At the first sign or symptom of cardiac failure, patients receiving timolol should be digitalized and/or be given a diuretic, and the response observed closely. If cardiac failure continues, despite adequate digitalization and diuretic therapy, timolol should be withdrawn. Exacerbation of Ischemic Heart Disease Following Abrupt Withdrawal Hypersensitivity to catecholamines has been observed in patients withdrawn from beta-blocker therapy; exacerbation of angina and, in some cases, myocardial infarction have occurred after abrupt discontinuation of such therapy. When discontinuing chronically administered timolol maleate, particularly in patients with ischemic heart disease, the dosage should be gradually reduced over a period of one to two weeks and the patient should be carefully monitored. If angina markedly worsens or acute coronary insufficiency develops, timolol maleate administration should be reinstituted promptly, at least temporarily, and other measures appropriate for the management of unstable angina should be taken. Patients should be warned against interruption or discontinuation of therapy without the physician’s advice. Because coronary artery disease is common and may be unrecognized, it may be prudent not to discontinue timolol maleate therapy abruptly even in patients treated only for hypertension. Obstructive Pulmonary Disease PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (e.g., CHRONIC BRONCHITIS, EMPHYSEMA) OF MILD OR MODERATE SEVERITY, BRONCHOSPASTIC DISEASE OR A HISTORY OF BRONCHOSPASTIC DISEASE (OTHER THAN BRONCHIAL ASTHMA OR A HISTORY OF BRONCHIAL ASTHMA, IN WHICH ‘TIMOLOL MALEATE’ IS CONTRAINDICATED, see CONTRAINDICATIONS ), SHOULD IN GENERAL NOT RECEIVE BETA-BLOCKERS, INCLUDING ‘TIMOLOL’. However, if timolol is necessary in such patients, then the drug should be administered with caution since it may block bronchodilation produced by endogenous and exogenous catecholamine stimulation of beta 2 receptors. Major Surgery The necessity or desirability of withdrawal of beta-blocking therapy prior to major surgery is controversial. Beta-adrenergic receptor blockade impairs the ability of the heart to respond to beta-adrenergically mediated reflex stimuli. This may augment the risk of general anesthesia in surgical procedures. Some patients receiving beta-adrenergic receptor blocking agents have been subject to protracted severe hypotension during anesthesia. Difficulty in restarting and maintaining the heartbeat has also been reported. For these reasons, in patients undergoing elective surgery, some authorities recommend gradual withdrawal of beta-adrenergic receptor blocking agents. If necessary during surgery, the effects of beta-adrenergic blocking agents may be reversed by sufficient doses of such agonists as isoproterenol, dopamine, dobutamine or norepinephrine (see OVERDOSAGE ). Diabetes Mellitus Timolol should be administered with caution in patients subject to spontaneous hypoglycemia or to diabetic patients (especially those with labile diabetes) who are receiving insulin or oral hypoglycemic agents. Beta-adrenergic receptor blocking agents may mask the signs and symptoms of acute hypoglycemia. Thyrotoxicosis Beta-adrenergic blockade may mask certain clinical signs (e.g., tachycardia) of hyperthyroidism. Patients suspected of developing thyrotoxicosis should be managed carefully to avoid abrupt withdrawal of beta-blockade which might precipitate a thyroid storm.
Exacerbation of Ischemic Heart Disease Following Abrupt Withdrawal
Hypersensitivity to catecholamines has been observed in patients withdrawn from beta-blocker therapy; exacerbation of angina and, in some cases, myocardial infarction have occurred after abrupt discontinuation of such therapy. When discontinuing chronically administered timolol maleate, particularly in patients with ischemic heart disease, the dosage should be gradually reduced over a period of one to two weeks and the patient should be carefully monitored. If angina markedly worsens or acute coronary insufficiency develops, timolol maleate administration should be reinstituted promptly, at least temporarily, and other measures appropriate for the management of unstable angina should be taken. Patients should be warned against interruption or discontinuation of therapy without the physician’s advice. Because coronary artery disease is common and may be unrecognized, it may be prudent not to discontinue timolol maleate therapy abruptly even in patients treated only for hypertension.

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