timolol (Betimol)

What is timolol and how does it work (mechanism of action)?

Timolol GFS 0.25% and 0.5% are indicated for the treatment of elevated intraocular pressure in patients with ocular hypertension or open-angle glaucoma.

Timolol maleate is a beta1 and beta2 (nonselective) adrenergic receptor inhibitor that does not have significant intrinsic sympathomimetic, direct myocardial depressant, or local anesthetic (membrane-stabilizing) activity. Timolol GFS, when applied topically to the eye, has the action of reducing elevated, as well as normal, intraocular pressure, whether or not accompanied by glaucoma.

Elevated intraocular pressure is a major risk factor in the pathogenesis of glaucomatous visual field loss and optic nerve damage. The precise mechanism of the ocular hypotensive action of Timolol GFS is not clearly established at this time.

Is timolol available as a generic drug?


Do I need a prescription for timolol?


What are the uses for timolol?

What are the side effects of timolol?

Minor side effects of timolol include:

Major side effects include:

What is the dosage for timolol?

The range of dosing for adults is 10 to 60 mg per day.


In the U.S., 1 in every 4 deaths is caused by heart disease. See Answer

Which drugs or supplements interact with timolol?

  • The concurrent use of timolol and clonidine (Catapres), may cause rebound hypertension upon abrupt discontinuation of clonidine. It is advisable, therefore, to stop the beta adrenergic blocking drug by several days before gradually withdrawing clonidine.
  • Fenoldopam (Corlopam), which is used for the treatment of severe hypertension should not be taken together with timolol as the combination may increase the risk of hypotension due to additive effects of the two drugs in lowering blood pressure.
  • Close observation should be carried out when timolol is administered to patients receiving catecholamine-depleting drugs such as reserpine (Harmonyl) because of possible additive effects and the production of hypotension and/or a markedly slow heartbeat, which may produce dizziness, syncope, or postural hypotension (dizziness upon standing).
  • Concurrent use of NSAIDs with timolol may cause the antihypertensive action of beta-blockers to be decreased. This occurs because prostaglandins are important in controlling blood pressure.

Is timolol safe to take if I'm pregnant or breastfeeding?

  • There are no adequate studies in pregnant women. Timolol should be used during pregnancy only if the potential benefit justifies the potential risk.
  • Timolol has been detected in human milk and has a potential for adverse events in infants.

What else should I know about timolol?

What preparations of timolol are available?

Tablets: 5, 10, and 20 mg.

How should I keep timolol stored?

Timolol should be stored at room temperature, 15 C - 30 C (59 F - 86 F) and kept in a tightly sealed container protected from light


Timolol (Betimol) is a first-generation beta-blocker drug. Timolol is prescribed for the treatment of high blood pressure, angina, heart attacks, and migraine headache prevention. Off label uses include treatment for cardiomyopathy and mitral valve prolapse. Side effects include fatigue, insomnia, nausea, vomiting, diarrhea, abdominal cramps. Drug interactions, warnings and precautions, and pregnancy and breastfeeding safety information should be reviewed prior to taking this medication.

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