New drugs in hypertension.

Clonidine, propranolol, bethanidine and debrisoquine effectively decrease blood pressure by suppressing renin secretion or interfering with function of the sympathetic nervous system. In man these compounds exert an antihypertensive effect within several hours or days and their duration of action is sufficient to permit administration twice or thrice daily. Clonidine and propranolol are especially useful if sexual dysfunction or postural hypotension is undesirable. Although bethanidine and debrisoquine may produce these adverse effects, they are beneficial in severe hypertension and produce fewer side effects than guanethidine. Clonidine frequently causes sedation, and rebound hypertension may occur with sudden cessation of therapy. Injudicious use of propranolol may provoke heart failure or asthma in susceptible individuals. The combination of a thiazide diuretic with propranolol and one of hydralazine, bethanidine and debrisoquine may be used to treat severe or complicated hypertension.