When therapy with Timolol is discontinued, the blood pressure tends to return to pretreatment levels gradually. Dosage adjustment to achieve optimal antihypertensive effect may require a few weeks. In the majority of patients with hypertension Timolol also decreases plasma renin activity. Plasma volume may decrease or remain unchanged during therapy with Timolol. With continued administration of Timolol, blood pressure decreases within a few days, cardiac output usually remains reduced, and peripheral resistance falls toward pretreatment levels. Administration of Timolol to patients with hypertension results initially in a decrease in cardiac output, little immediate change in blood pressure, and an increase in calculated peripheral resistance. Such an effect in patients with asthma or other bronchospastic conditions is potentially dangerous.Ĭlinical studies indicate that Timolol maleate at a dosage of 20 to 60 mg/day reduces blood pressure without causing postural hypotension in most patients with essential hypertension. In patients with severe impairment of myocardial function beta-adrenergic receptor blockade may inhibit the stimulatory effect of the sympathetic nervous system necessary to maintain adequate cardiac function.īeta-adrenergic receptor blockade in the bronchi and bronchioles results in increased airway resistance from unopposed parasympathetic activity. In normal volunteers, the reduction in heart rate response to a standard exercise was dose dependent over the test range of 0.5 to 20 mg, with a peak reduction at 2 hours of approximately 30% at higher doses.īeta-adrenergic receptor blockade reduces cardiac output in both healthy subjects and patients with heart disease. ![]() ![]() The magnitude of this decreased response is proportional to the existing sympathetic tone and the concentration of Timolol at receptor sites. ![]() Timolol decreases the positive chronotropic, positive inotropic, bronchodilator, and vasodilator responses caused by beta-adrenergic receptor agonists. PharmacodynamicsĬlinical pharmacology studies have confirmed the beta-adrenergic blocking activity as shown by (1) changes in resting heart rate and response of heart rate to changes in posture (2) inhibition of isoproterenol-induced tachycardia (3) alteration of the response to the Valsalva maneuver and amyl nitrite administration and (4) reduction of heart rate and blood pressure changes on exercise. Timolol maleate is a beta1 and beta2 (nonselective) adrenergic receptor blocking agent that does not have significant intrinsic sympathomimetic, direct myocardial depressant, or local anesthetic activity. Related/similar drugs Botox, amlodipine, lisinopril, aspirin, metoprolol, losartan, furosemide CLINICAL PHARMACOLOGY
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