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

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... rawal 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 a greater reduction in systolic, mean and diastolic blood pressures and a smaller reduction in resting heart rate than propranolol, presumably reflecting its partial agonist and cardioselective properties during similar dosetitration phases. Exercise duration and exercise work improved similarly with each agent. Acebutolol and propranolol significantly and comparably reduced anginal frequency (56% and 54%, respectively,p < 0.001) and weekly nitroglycerin consumption (57% and 47%, respectively,p < 0.01) compared with placebo. No clinical or laboratory side effects of acebutolol or propranolol necessitated drug withdrawal. We conclude that acebutolol is a well-tolerated and safe (-adrenergic blocking agent that possesses cardioselective and mild intrinsic sympathomimetic activities and compares favorably with propranolol in antianginal efficacy in patients with chronic stable angina.