Placebo-controlled Study

The effects of oral acebutolol, a cardioselective f-adrenergic blocking agent with partial agonist activity were compared with those of oral propranolol, a noncardioselective agent devoid of partial agonist activity, on the exercise tolerance and anginal pattern in 46 male patients with chronic stable angina pectoris. A 28-week, multicenter, placebo-controlled, randomized, double-blind, crossover study design was used. Each double-blind treatment phase was followed by a 2-week gradual drug-withdrawal phase and a placebo-controlled drug-free week. Angina frequency, nitroglycerin consumption and symptom-limited exercise tests were assessed throughout the study. Acebutolol and propranolol produced comparable levels of blockade at 1650 ± 375 mg/day and 219 ± 50 mg/day (mean ± SD), respectively, as confirmed by a significant reduction in resting and peak exercise heart rates and rate-pressure products. Compared with placebo (acebutolol vs propranolol, NS), acebutolol produced