Effect of propranolol on elevated arterial blood pressure.

PRONETHALOL, an effective beta-adrenergic blocking agent, was observed to reduce arterial blood pressure in hypertensive patients being treated for angina pectoris.1 Subsequently Prichard and Gillam2 3 compared propranolol, another beta-adrenergic blocking drug, 120 to 640 mg/day, with previously administered methyldopa in 12 hypertensive patients and reported lower blood pressure during use of propranolol. Since in previous clinical trials2-6 the hypotensive effect of propranolol was not compared with that of placebo, we have evaluated the hypotensive efficacy of propranolol in comparison with that of inert tablets and a standard diuretic in trials in which neither physician nor pa-