Effect of minoxidil on blood pressure and hemodynamics in severe hypertension.

Eighteen patients with diastolic hypertension (100 to 120 mm Hg), in addition to propranolol, 160 mg daily, and hydrochlorothiazide, 100 mg daily, received progressively increased doses of either minoxidil or placebo in a double-blind crossover study. With minoxidil (average dose 19.7 mg) blood pressure decreased from 165/109 to 138/89 mm Hg without the appearance of orthostatic hypotension. Hypertrichosis and fluid retention did occur, with an average weight gain of 1.8 kg, concomitant with an increased plasma volume. Pulse rate and cardiac output increased; no significant changes were observed in plasma renin activity, renal plasma flow, glomerular filtration rate or excretion of catecholamines or aldosterone. Minoxidil appears to be a useful antihypertensive drug for treating patients who do not respond adequately to therapy with diuretic and beta adrenergic blocking agents.