Timolol

— THERAPEUTIC CATEGORIES —
  • Hypertension
  • Migraine and headache
  • Thromboembolic disorders
PAGE CONTENTS
  • Jump to Section
  • Generic Name & Formulations
  • Indications
  • Dosage and Administration
  • Contraindications
  • Boxed Warnings
  • Warnings/Precautions
  • Pharmacokinetics
  • Interactions
  • Adverse Reactions
  • Clinical Trials
  • Note
  • Patient Counseling

    • Timolol Generic Name & Formulations

    Legal Class

    Rx

    General Description

    Timolol maleate 5mg, 10mg+, 20mg+; tabs; +scored.

    Pharmacological Class

    Beta-blocker.

    How Supplied

    Contact supplier

    Storage

    Store at 20° to 25°C (68° to 77°F). Protect from light.

     

    Manufacturer

    Various generic manufacturers

    Timolol Indications

    Indications

    Hypertension.

    Timolol Dosage and Administration

    Adult

    Initially 10mg twice daily. Increase weekly if needed. Usual maintenance: 20–40mg/day; max 60mg/day in 2 divided doses.

    Children

    Not recommended.

    Timolol Contraindications

    Contraindications

    Asthma. Severe COPD. Sinus bradycardia. 2nd- or 3rd-degree AV block. Overt heart failure. Cardiogenic shock.

    Timolol Boxed Warnings

    Not Applicable

    Timolol Warnings/Precautions

    Warnings/Precautions

    CHF. Ischemic heart disease. Bronchospastic disease, COPD. Renal or hepatic dysfunction. Diabetes. Hyperthyroidism. Cerebrovascular insufficiency. Surgery. SLE. Avoid abrupt cessation. Pregnancy (Cat.C). Nursing mothers: not recommended.

    Warnings/Precautions

    Cardiac Failure

    • In patients with diminished myocardial contractility, sympathetic stimulation may be essential for support of circulation.
    • Inhibition by beta-adrenergic receptor blockers may precipitate more severe cardiac failure. 
    • Generally, beta blockers should be avoided in overt congestive heart failure, though they may be used with caution in patients with a history of failure who are well compensated (usually with digitalis and diuretics).
    • Digitalis and timolol both slow AV conduction; if cardiac failure persists, timolol should be withdrawn.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; observe closely and treat. If cardiac failure continues, withdraw timolol.

    Exacerbation of Ischemic Heart Disease After Abrupt Withdrawal

    • Hypersensitivity to catecholamines, exacerbation of angina, and myocardial infarction have all been reported following abrupt discontinuation of beta blockers.
    • When discontinuing treatment, gradually reduce the dosage of timolol over a period of 1 to 2 weeks, especially in patients with ischemic heart disease.
    • If angina worsens or acute coronary insufficiency develops, restart timolol temporarily and employ other measures for managing unstable angina.
    • Avoid abrupt discontinuation of timolol even if patients are only being treated for hypertension.

    Obstructive Pulmonary Disease

    • Contraindicated in patients with bronchial asthma or a history of bronchial asthma or severe chronic obstructive pulmonary disease (COPD).
    • Avoid in patients with COPD or in those with mild or moderate bronchospastic disease or a history of bronchospastic disease.
    • If timolol is needed, administer with caution since it may block bronchodilation produced by endogenous and exogenous catecholamine stimulation of beta2-receptors.

    Major Surgery

    • Some authorities recommend gradual withdrawal of beta-adrenergic receptor blocking agents in patients undergoing elective surgery as they may augment the risk of general anesthesia.
    • If necessary during surgery, the effects of beta-adrenergic blocking agents may be reversed by sufficient doses of isoproterenol, dopamine, dobutamine, or norepinephrine.

    Diabetes Mellitus

    • Beta-adrenergic receptor blocking agents may mask the signs/symptoms of acute hypoglycemia.
    • Administer with caution to patients with diabetes receiving insulin/oral hypoglycemic agents or those who experience spontaneous hypoglycemia.

    Thyrotoxicosis

    • Beta-adrenergic blockers may mask certain signs of hyperthyroidism.
    • Avoid abrupt withdrawal of beta blockers in patients suspected of developing thyrotoxicosis as this may precipitate a thyroid storm.

    Muscle Weakness

    • Timolol has been rarely reported to increase muscle weakness in some patients with myasthenia gravis or myasthenic symptoms.

    Cerebrovascular Insufficiency

    • Signs/symptoms of reduced cerebral blood flow: Consider discontinuing timolol.

    Risk of Anaphylactic Reaction

    • History of atopy or severe anaphylactic reaction to a variety of allergens: Patients on beta blockers may be more reactive to repeated accidental, diagnostic, or therapeutic challenge with such allergens.

    • Patients may be unresponsive to usual doses of epinephrine used to treat anaphylactic reactions.

    Pregnancy Considerations

    No adequate and well controlled studies in pregnant women. Timolol should only be used in pregnant patients if the potential benefits outweigh the potential risk to the fetus.

    Nursing Mother Considerations

    Timolol has been detected in human milk. A decision should be made whether to discontinue nursing or discontinue timolol.

    Pediatric Considerations

    Safety and effectiveness in pediatric patients have not been established.

    Geriatric Considerations

    Clinical studies of timolol for hypertension did not include a sufficient number of patients 65 years and over.

    Renal Impairment Considerations

    Timolol is excreted mainly by the kidneys; dose reductions may be necessary in patients with renal insufficiency. 

    Marked hypotensive responses have been seen in patients with renal impairment undergoing dialysis after 20mg doses; use with caution in these patients.

    Hepatic Impairment Considerations

    Timolol is partially metabolized in the liver; dose reductions may be necessary in patients with hepatic insufficiency.

    Timolol Pharmacokinetics

    Absorption

    Rapidly and nearly completely absorbed (~90%) following oral ingestion.

    Peak plasma levels occur within 1 to 2 hours.

    Distribution

    Not extensively bound to plasma proteins.

    Metabolism

    Hepatic.

    Elimination

    Renal. Half-life: ~4hrs.

    Timolol Interactions

    Interactions

    Hypotension, bradycardia with catecholamine-depleting drugs. May increase cardiac effects of calcium channel blockers, digitalis. May be potentiated by quinidine. Increased rebound hypertension with clonidine withdrawal. Antagonized by NSAIDs. Adjust antidiabetic medications. May interfere with glaucoma screening tests. May block epinephrine.

    Timolol Adverse Reactions

    Adverse Reactions

    Cardiac failure, bronchospasm, asthenia, bradycardia, dizziness, arrhythmia, heart block, dyspnea, muscle weakness, cold extremities, decreased libido, chest pain, syncope, pruritus.

    Timolol Clinical Trials

    Clinical Trials

    Clinical studies indicate that timolol maleate at a dosage of 20-60 mg/day reduces blood pressure (BP) without causing postural hypotension in most patients with essential hypertension. Administration of timolol results initially in a decrease in cardiac output, little immediate change in BP, and an increase in calculated peripheral resistance. 

    With continued administration, BP 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. Timolol also decreases plasma renin activity in the majority of patients with hypertension. 

    Dosage adjustment to achieve optimal antihypertensive effect may require a few weeks. When therapy with timolol is discontinued, BP 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.

    Timolol Note

    Notes

    Formerly known under the brand name Blocadren.

    Timolol Patient Counseling

    Patient Counseling

    Do not interrupt or discontinue therapy abruptly.

    Timolol Generic Name & Formulations

    Legal Class

    Rx

    General Description

    Timolol maleate 5mg, 10mg+, 20mg+; tabs; +scored.

    Pharmacological Class

    Beta-blocker.

    How Supplied

    Contact supplier

    Storage

    Store at 20° to 25°C (68° to 77°F). Protect from light.

     

    Manufacturer

    Various generic manufacturers

    Timolol Indications

    Indications

    Migraine prophylaxis.

    Timolol Dosage and Administration

    Adult

    Initially 10mg twice daily. Increase weekly if needed; max 30mg daily in 2 divided doses. Evaluate at 6–8 wks.

    Children

    Not recommended.

    Timolol Contraindications

    Contraindications

    Asthma. Severe COPD. Sinus bradycardia. 2nd- or 3rd-degree AV block. Overt heart failure. Cardiogenic shock.

    Timolol Boxed Warnings

    Not Applicable

    Timolol Warnings/Precautions

    Warnings/Precautions

    CHF. Ischemic heart disease. Bronchospastic disease, COPD. Renal or hepatic dysfunction. Diabetes. Hyperthyroidism. Cerebrovascular insufficiency. Surgery. SLE. Avoid abrupt cessation. Pregnancy (Cat.C). Nursing mothers: not recommended.

    Warnings/Precautions

    Cardiac Failure

    • In patients with diminished myocardial contractility, sympathetic stimulation may be essential for support of circulation.
    • Inhibition by beta-adrenergic receptor blockers may precipitate more severe cardiac failure. 
    • Generally, beta blockers should be avoided in overt congestive heart failure, though they may be used with caution in patients with a history of failure who are well compensated (usually with digitalis and diuretics).
    • Digitalis and timolol both slow AV conduction; if cardiac failure persists, timolol 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; observe closely and treat. If cardiac failure continues, withdraw timolol.

    Exacerbation of Ischemic Heart Disease After Abrupt Withdrawal

    • Hypersensitivity to catecholamines, exacerbation of angina, and myocardial infarction have all been reported following abrupt discontinuation of beta blockers.
    • When discontinuing treatment, gradually reduce the dosage of timolol over a period of 1 to 2 weeks, especially in patients with ischemic heart disease.
    • If angina worsens or acute coronary insufficiency develops, restart timolol temporarily and employ other measures for managing unstable angina.
    • Avoid abrupt discontinuation of timolol even if patients are only being treated for hypertension.

    Obstructive Pulmonary Disease

    • Contraindicated in patients with bronchial asthma or a history of bronchial asthma or severe chronic obstructive pulmonary disease (COPD).
    • Avoid in patients with COPD or in those with mild or moderate bronchospastic disease or a history of bronchospastic disease.
    • If timolol is needed, administer with caution since it may block bronchodilation produced by endogenous and exogenous catecholamine stimulation of beta2-receptors.

    Major Surgery

    • Some authorities recommend gradual withdrawal of beta-adrenergic receptor blocking agents in patients undergoing elective surgery as they may augment the risk of general anesthesia.
    • If necessary during surgery, the effects of beta-adrenergic blocking agents may be reversed by sufficient doses of isoproterenol, dopamine, dobutamine, or norepinephrine.

    Diabetes Mellitus

    • Beta-adrenergic receptor blocking agents may mask the signs/symptoms of acute hypoglycemia.
    • Administer with caution to patients with diabetes receiving insulin/oral hypoglycemic agents or those who experience spontaneous hypoglycemia.

    Thyrotoxicosis

    • Beta-adrenergic blockers may mask certain signs of hyperthyroidism.
    • Avoid abrupt withdrawal of beta blockers in patients suspected of developing thyrotoxicosis as this may precipitate a thyroid storm.

    Muscle Weakness

    • Timolol has been rarely reported to increase muscle weakness in some patients with myasthenia gravis or myasthenic symptoms.

    Cerebrovascular Insufficiency

    • Signs/symptoms of reduced cerebral blood flow: Consider discontinuing timolol.

    Risk of Anaphylactic Reaction

    • History of atopy or severe anaphylactic reaction to a variety of allergens: Patients on beta blockers may be more reactive to repeated accidental, diagnostic, or therapeutic challenge with such allergens.

    • Patients may be unresponsive to usual doses of epinephrine used to treat anaphylactic reactions.

    Pregnancy Considerations

    No adequate and well controlled studies in pregnant women. Timolol should only be used in pregnant patients if the potential benefits outweigh the potential risk to the fetus.

    Nursing Mother Considerations

    Timolol has been detected in human milk. A decision should be made whether to discontinue nursing or discontinue timolol.

    Pediatric Considerations

    Safety and effectiveness in pediatric patients have not been established.

    Geriatric Considerations

    Clinical studies of timolol for migraine did not include a sufficient number of patients 65 years and over.

    Renal Impairment Considerations

    Timolol is excreted mainly by the kidneys; dose reductions may be necessary in patients with renal insufficiency. 

    Marked hypotensive responses have been seen in patients with renal impairment undergoing dialysis after 20mg doses; use with caution in these patients.

    Hepatic Impairment Considerations

    Timolol is partially metabolized in the liver; dose reductions may be necessary in patients with hepatic insufficiency.

    Timolol Pharmacokinetics

    Absorption

    Rapidly and nearly completely absorbed (~90%) following oral ingestion.

    Peak plasma levels occur within 1 to 2 hours.

    Distribution

    Not extensively bound to plasma proteins.

    Metabolism

    Hepatic.

    Elimination

    Renal. Half-life: ~4hrs.

    Timolol Interactions

    Interactions

    Hypotension, bradycardia with catecholamine-depleting drugs. May increase cardiac effects of calcium channel blockers, digitalis. May be potentiated by quinidine. Increased rebound hypertension with clonidine withdrawal. Antagonized by NSAIDs. Adjust antidiabetic medications. May interfere with glaucoma screening tests. May block epinephrine.

    Timolol Adverse Reactions

    Adverse Reactions

    Cardiac failure, bronchospasm, asthenia, bradycardia, dizziness, arrhythmia, heart block, dyspnea, muscle weakness, cold extremities, decreased libido, chest pain, syncope, pruritus.

    Timolol Clinical Trials

    Clinical Trials

    The efficacy of timolol for the prophylactic treatment of migraine was evaluated in a placebo-controlled clinical trial that included 400 patients (18-66 years old; mostly female). The most frequent diagnosis was common migraine with all patients having at least 2 headaches per month at baseline. 

    Findings showed a greater proportion of timolol-treated patients had a reduction in the frequency of migraine headache of at least 50%, compared with those who received placebo (50% vs 30%, respectively). The most common cardiovascular adverse effect was bradycardia (5%).

    Timolol Note

    Notes

    Formerly known under the brand name Blocadren.

    Timolol Patient Counseling

    Patient Counseling

    Do not interrupt or discontinue therapy abruptly.

    Timolol Generic Name & Formulations

    Legal Class

    Rx

    General Description

    Timolol maleate 5mg, 10mg+, 20mg+; tabs; +scored.

    Pharmacological Class

    Beta-blocker.

    How Supplied

    Contact supplier

    Storage

    Store at 20° to 25°C (68° to 77°F). Protect from light.

     

    Manufacturer

    Various generic manufacturers

    Timolol Indications

    Indications

    In stabilized patients after MI, to reduce mortality and risk of reinfarction.

    Timolol Dosage and Administration

    Adult

    10mg twice daily.

    Children

    Not recommended.

    Timolol Contraindications

    Contraindications

    Asthma. Severe COPD. Sinus bradycardia. 2nd- or 3rd-degree AV block. Overt heart failure. Cardiogenic shock.

    Timolol Boxed Warnings

    Not Applicable

    Timolol Warnings/Precautions

    Warnings/Precautions

    CHF. Ischemic heart disease. Bronchospastic disease, COPD. Renal or hepatic dysfunction. Diabetes. Hyperthyroidism. Cerebrovascular insufficiency. Surgery. SLE. Avoid abrupt cessation. Pregnancy (Cat.C). Nursing mothers: not recommended.

    Warnings/Precautions

    Cardiac Failure

    • In patients with diminished myocardial contractility, sympathetic stimulation may be essential for support of circulation.
    • Inhibition by beta-adrenergic receptor blockers may precipitate more severe cardiac failure. 
    • Generally, beta blockers should be avoided in overt congestive heart failure, though they may be used with caution in patients with a history of failure who are well compensated (usually with digitalis and diuretics).
    • Digitalis and timolol both slow AV conduction; if cardiac failure persists, timolol 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; observe closely and treat. If cardiac failure continues, withdraw timolol.

    Exacerbation of Ischemic Heart Disease After Abrupt Withdrawal

    • Hypersensitivity to catecholamines, exacerbation of angina, and myocardial infarction have all been reported following abrupt discontinuation of beta blockers.
    • When discontinuing treatment, gradually reduce the dosage of timolol over a period of 1 to 2 weeks, especially in patients with ischemic heart disease.
    • If angina worsens or acute coronary insufficiency develops, restart timolol temporarily and employ other measures for managing unstable angina.
    • Avoid abrupt discontinuation of timolol even if patients are only being treated for hypertension.

    Obstructive Pulmonary Disease

    • Contraindicated in patients with bronchial asthma or a history of bronchial asthma or severe chronic obstructive pulmonary disease (COPD).
    • Avoid in patients with COPD or in those with mild or moderate bronchospastic disease or a history of bronchospastic disease.
    • If timolol is needed, administer with caution since it may block bronchodilation produced by endogenous and exogenous catecholamine stimulation of beta2-receptors.

    Major Surgery

    • Some authorities recommend gradual withdrawal of beta-adrenergic receptor blocking agents in patients undergoing elective surgery as they may augment the risk of general anesthesia.
    • If necessary during surgery, the effects of beta-adrenergic blocking agents may be reversed by sufficient doses of isoproterenol, dopamine, dobutamine, or norepinephrine.

    Diabetes Mellitus

    • Beta-adrenergic receptor blocking agents may mask the signs/symptoms of acute hypoglycemia.
    • Administer with caution to patients with diabetes receiving insulin/oral hypoglycemic agents or those who experience spontaneous hypoglycemia.

    Thyrotoxicosis

    • Beta-adrenergic blockers may mask certain signs of hyperthyroidism.
    • Avoid abrupt withdrawal of beta blockers in patients suspected of developing thyrotoxicosis as this may precipitate a thyroid storm.

    Muscle Weakness

    • Timolol has been rarely reported to increase muscle weakness in some patients with myasthenia gravis or myasthenic symptoms.

    Cerebrovascular Insufficiency

    • Signs/symptoms of reduced cerebral blood flow: Consider discontinuing timolol.

    Risk of Anaphylactic Reaction

    • History of atopy or severe anaphylactic reaction to a variety of allergens: Patients on beta blockers may be more reactive to repeated accidental, diagnostic, or therapeutic challenge with such allergens.

    • Patients may be unresponsive to usual doses of epinephrine used to treat anaphylactic reactions.

    Pregnancy Considerations

    No adequate and well controlled studies in pregnant women. Timolol should only be used in pregnant patients if the potential benefits outweigh the potential risk to the fetus.

    Nursing Mother Considerations

    Timolol has been detected in human milk. A decision should be made whether to discontinue nursing or discontinue timolol.

    Pediatric Considerations

    Safety and effectiveness in pediatric patients have not been established.

    Geriatric Considerations

    In a clinical study evaluating timolol for the reduction of mortality and risk of reinfarction, safety and efficacy were not found to be different between older patients and younger patients.

    In general, dose selection in older patients should be cautious. The drug is substantially excreted by the kidney; adverse events may be greater in patients with impaired renal function.

    Renal Impairment Considerations

    Timolol is excreted mainly by the kidneys; dose reductions may be necessary in patients with renal insufficiency. 

    Marked hypotensive responses have been seen in patients with renal impairment undergoing dialysis after 20mg doses; use with caution in these patients.

    Hepatic Impairment Considerations

    Timolol is partially metabolized in the liver; dose reductions may be necessary in patients with hepatic insufficiency.

    Timolol Pharmacokinetics

    Absorption

    Rapidly and nearly completely absorbed (~90%) following oral ingestion.

    Peak plasma levels occur within 1 to 2 hours.

    Distribution

    Not extensively bound to plasma proteins.

    Metabolism

    Hepatic.

    Elimination

    Renal. Half-life: ~4hrs.

    Timolol Interactions

    Interactions

    Hypotension, bradycardia with catecholamine-depleting drugs. May increase cardiac effects of calcium channel blockers, digitalis. May be potentiated by quinidine. Increased rebound hypertension with clonidine withdrawal. Antagonized by NSAIDs. Adjust antidiabetic medications. May interfere with glaucoma screening tests. May block epinephrine.

    Timolol Adverse Reactions

    Adverse Reactions

    Cardiac failure, bronchospasm, asthenia, bradycardia, dizziness, arrhythmia, heart block, dyspnea, muscle weakness, cold extremities, decreased libido, chest pain, syncope, pruritus.

    Timolol Clinical Trials

    Clinical Trials

    Timolol maleate was compared with placebo In a double-blind study that included 1884 patients (20-75 years old) who had survived the acute phase of a myocardial infarction. Treatment with timolol, started 7 to 28 days following infarction, resulted in reduced overall mortality when compared with placebo; this effect was primarily attributable to a reduction in cardiovascular mortality.

    Timolol also significantly reduced the incidence of sudden death and the incidence of nonfatal reinfarction. An analysis of data showed that the treatment effect was clearest for patients with a first infarction who were considered at a high risk of dying.

    Timolol Note

    Notes

    Formerly known under the brand name Blocadren.

    Timolol Patient Counseling

    Patient Counseling

    Do not interrupt or discontinue therapy abruptly.

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