Comparison of antianginal actions of verapamil and propranolol

Verapamil is a slow calcium channel blocker that has been in clinical use for almost 20 years as an antiarrhythmic agent. It also has an antianginal action,' but inconsistent results have been obtained in clinical trials owing to insufficient dosage.2 We found that the drug produced a significant decrease in the number of anginal attacks and the consumption of glyceryl trinitrate with improvement in exercise tolerance and ST changes when used in a dose of 360 mg daily.3 We have now compared the potency and mode of action of verapamil with those of propranolol, a standard beta-adrenergicreceptor-blocking drug, using fixed high doses of each.