Timolol is a non-selective beta-adrenergic blocker used in the treatment of elevated intraocular pressure in ocular hypertension or open angle glaucoma. Timolol competes with adrenergic neurotransmitters for binding to beta(1)-adrenergic receptors in the heart and the beta(2)-receptors in the vascular and bronchial smooth muscle. This leads to diminished actions of catecholamines, which normally bind to adrenergic receptors and exert sympathetic effects leading to an increase in blood pressure and heart rate. Beta(1)-receptor blockade by timolol leads to a decrease in both heart rate and cardiac output during rest and exercise, and a decrease in both systolic and diastolic blood pressure. In addition to this, a reduction in reflex orthostatic hypotension may also occur. Timolol, when administered by the ophthalmic route, rapidly reduces intraocular pressure. When administered in the tablet form, it reduces blood pressure, heart rate, and cardiac output, and decreases sympathetic activity. It can be found under the brand names Azarga, Betimol, Combigan, Cosopt, Duotrav, Istalol, Timoptic, and Xalacom. Some side effects of using Timolol may include eye pain, swollen eyelids, and dry mouth.

Timolol B1-Adrenergic Cardiac Muscle Relaxation Pathway References