timolol, Blocadren, Timolide 10-25

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BRAND NAME: Blocadren, Timolide 10-25 (These brands are no longer available in the U.S.)

DRUG CLASS AND MECHANISM: Timolol is a beta-adrenergic blocking drug that is used to treat high blood pressure, angina (heart pain), heart attacks and to prevent migraine headaches. Timolol is a first generation beta blocker in a class that includes propranolol (Inderal, InnoPran), nadolol (Corgard), penbutolol sulfate (Levatol), sotalol hydrochloride (Betapace), and pindolol (Visken). They differ from other beta blockers because they are non-selective in nature, meaning that they block both beta-1 and beta-2 receptors on nerves and, therefore, will affect not only the heart but also the kidneys, lungs, gastrointestinal tract, liver, uterus, muscles surrounding blood vessels, and skeletal muscle. As a result, they could cause such effects as reduced pumping of blood by the heart and reduced kidney function among other actions. Timolol specifically works by blocking the stimulating actions of the sympathetic nervous system thereby allowing the heart to relax and beat more slowly. This reduces the amount of blood that the heart must pump. Timolol was approved by the FDA in November 1981.



PREPARATIONS: Tablets: 5, 10, and 20 mg.

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

PRESCRIBED FOR: Timolol is prescribed to lower blood pressure in patients with high blood pressure (hypertension). It also is used to reduce angina (heart pain), and to stabilize irregular heartbeats (arrhythmias) and prevent migraine headaches. Off label uses include the treatment of hypertrophic cardiomyopathy and mitral valve prolapse.

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

DRUG INTERACTIONS: 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.

PREGNANCY: There are no adequate studies in pregnant women. Timolol should be used during pregnancy only if the potential benefit justifies the potential risk.

NURSING MOTHERS: Timolol has been detected in human milk and has a potential for adverse events in infants.

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