Propranolol versus verapamil for the treatment of essential hypertension

Recent reports have confirmed that slow calcium channel inhibitors have useful antihypertensive properties because they produce dilatation of the peripheral arterioles without reflex tachycardia. Their clinical place in the management of hypertension has yet to be clearly defined, and thus we have performed an open crossover trial to compare the 24-hour profiles of blood pressure reduction after chronic therapy with propranolol and verapamil. Nineteen patients were studied by continuous ambulatory intraarterial recording and the order of drug administration was decided by random allocation. Drug dosage was twice daily and titrated according to casual clinic pressures (propranolol, 40 to 240 mg twice a day; verapamil, 120 to 240 mg twice a day). Mean hourly blood pressure and heart rate values were obtained over a 24-hour cycle, and the responses to isometric and dynamic exercise were also examined. Both drugs were shown to produce a uniform and comparable reduction in blood pressure throughout the whole day, together with a reduction in heart rate, which was greater with propranolol. Comparable effects were also seen on the pressor responses to exercise. Both drugs were equally well tolerated and caused no patient withdrawals. We conclude that oral verapamil given twice daily showed a similar degree of efficacy to propranolol and provided 24-hour blood pressure control. This slow calcium channel inhibitor may be useful as initial therapy for hypertension, particularly for those patients in whom beta-adrenoreceptor blockers are contraindicated.