Timolol

Generic Name: timolol

Over-the-Counter (OTC)

Brand Names:

Betimol

DESCRIPTION Betimol ® (timolol ophthalmic solution), 0.25% and 0.5%, is a non-selective beta-adrenergic antagonist for ophthalmic use. The chemical name of the active ingredient is (S)-1-[(1, 1-dimethylethyl)amino]-3-[[4-(4-morpholinyl)-1,2,5-thiadiazol-3-yl]oxy]-2-propanol. Timolol hemihydrate is the levo isomer. Specific rotation is [α] 25 405nm =-16° (C=10% as the hemihydrate form in 1N HCl).

Overview

DESCRIPTION Betimol ® (timolol ophthalmic solution), 0.25% and 0.5%, is a non-selective beta-adrenergic antagonist for ophthalmic use. The chemical name of the active ingredient is (S)-1-[(1, 1-dimethylethyl)amino]-3-[[4-(4-morpholinyl)-1,2,5-thiadiazol-3-yl]oxy]-2-propanol. Timolol hemihydrate is the levo isomer. Specific rotation is [α] 25 405nm =-16° (C=10% as the hemihydrate form in 1N HCl).

Uses

INDICATIONS AND USAGE Betimol ® is indicated in the treatment of elevated intraocular pressure in patients with ocular hypertension or open-angle glaucoma.

Dosage

DOSAGE AND ADMINISTRATION Betimol® Ophthalmic Solution is available in concentrations of 0.25% and 0.5%. The usual starting dose is one drop of 0.25% Betimol® in the affected eye(s) twice a day. If the clinical response is not adequate, the dosage may be changed to one drop of 0.5% solution in the affected eye(s) twice a day. If the intraocular pressure is maintained at satisfactory levels, the dosage schedule may be changed to one drop once a day in the affected eye(s). Because of diurnal variations in intraocular pressure, satisfactory response to the once-a-day dose is best determined by measuring the intraocular pressure at different times during the day.

Side Effects

ADVERSE REACTIONS The most frequently reported ocular event in clinical trials was burning/stinging on instillation and was comparable between Betimol ® and timolol maleate (approximately one in eight patients). The following adverse events were associated with use of Betimol ® in frequencies of more than 5% in two controlled, double-masked clinical studies in which 184 patients received 0.25% or 0.5% Betimol ® : OCULAR: Dry eyes, itching, foreign body sensation, discomfort in the eye, eyelid erythema, conjunctival injection, and headache. BODY AS A WHOLE: Headache. The following side effects were reported in frequencies of 1 to 5%: OCULAR: Eye pain, epiphora, photophobia, blurred or abnormal vision, corneal fluorescein staining, keratitis, blepharitis and cataract.

Interactions

Drug Interactions Beta-adrenergic blocking agents Patients who are receiving a beta-adrenergic blocking agent orally and Betimol ® should be observed for a potential additive effect either on the intraocular pressure or on the known systemic effects of beta-blockade. Patients should not usually receive two topical ophthalmic beta-adrenergic blocking agents concurrently. Catecholamine-depleting drugs Close observation of the patient is recommended when a beta-blocker 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.

Warnings

WARNINGS As with other topically applied ophthalmic drugs, Betimol ® is absorbed systemically. The same adverse reactions found with systemic administration of beta-adrenergic blocking agents may occur with topical administration. For example, severe respiratory and cardiac reactions, including death due to bronchospasm in patients with asthma, and rarely, death in association with cardiac failure have been reported following systemic or topical administration of beta-adrenergic blocking agents. 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 cardiac failure. CONTRAINDICATIONS Betimol ® is contraindicated in patients with overt heart failure, cardiogenic shock, sinus bradycardia, second- or third-degree atrioventricular block, bronchial asthma or history of bronchial asthma, or severe chronic obstructive pulmonary disease, or hypersensitivity to any component of this product.

Pregnancy

Pregnancy Teratogenic effects Category C Teratogenicity of timolol (as the maleate) after oral administration was studied in mice and rabbits. No fetal malformations were reported in mice or rabbits at a daily oral dose of 50 mg/kg (7,000 times the systemic exposure following the maximum recommended human ophthalmic dose). Although delayed fetal ossification was observed at this dose in rats, there were no adverse effects on postnatal development of offspring.

Storage

STORAGE Store between 15° to 25°C (59° to 77°F). Do not freeze. Protect from light.

Frequently Asked Questions

What is Timolol used for?

INDICATIONS AND USAGE Betimol ® is indicated in the treatment of elevated intraocular pressure in patients with ocular hypertension or open-angle glaucoma.

What are the side effects of Timolol?

ADVERSE REACTIONS The most frequently reported ocular event in clinical trials was burning/stinging on instillation and was comparable between Betimol ® and timolol maleate (approximately one in eight patients). The following adverse events were associated with use of Betimol ® in frequencies of more than 5% in two controlled, double-masked clinical studies in which 184 patients received 0.25% or 0.5% Betimol ® : OCULAR: Dry eyes, itching, foreign body sensation, discomfort in the eye, eyelid erythema, conjunctival injection, and headache. BODY AS A WHOLE: Headache. The following side effects were reported in frequencies of 1 to 5%: OCULAR: Eye pain, epiphora, photophobia, blurred or abnormal vision, corneal fluorescein staining, keratitis, blepharitis and cataract.

Can I take Timolol during pregnancy?

Pregnancy Teratogenic effects Category C Teratogenicity of timolol (as the maleate) after oral administration was studied in mice and rabbits. No fetal malformations were reported in mice or rabbits at a daily oral dose of 50 mg/kg (7,000 times the systemic exposure following the maximum recommended human ophthalmic dose). Although delayed fetal ossification was observed at this dose in rats, there were no adverse effects on postnatal development of offspring.

What are the important warnings for Timolol?

WARNINGS As with other topically applied ophthalmic drugs, Betimol ® is absorbed systemically. The same adverse reactions found with systemic administration of beta-adrenergic blocking agents may occur with topical administration. For example, severe respiratory and cardiac reactions, including death due to bronchospasm in patients with asthma, and rarely, death in association with cardiac failure have been reported following systemic or topical administration of beta-adrenergic blocking agents. 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 cardiac failure. CONTRAINDICATIONS Betimol ® is contraindicated in patients with overt heart failure, cardiogenic shock, sinus bradycardia, second- or third-degree atrioventricular block, bronchial asthma or history of bronchial asthma, or severe chronic obstructive pulmonary disease, or hypersensitivity to any component of this product.

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Medical Disclaimer

This drug information is for educational purposes only and should not replace professional medical advice. Drug information is sourced from the FDA National Drug Code Directory and Structured Product Labeling. Always consult with a healthcare provider before starting, stopping, or changing any medication.