Verapamil versus placebo in relieving stable angina pectoris.

Abstract

Verapamil and placebo were compared in patients with stable, effort-induced angina. Single-blind dose titration (240, 360 and 480 mg/day) preceded a double-blind crossover. Among the 18 patients who completed graded exercise stress tests with reproducible pretreatment effort-limiting angina, exercise duration increased from 348 .+-. 127 s (SD) before treatment to 494 .+-. 182 s after verapamil (P < 0.001), but did not change after placebo. Compared with placebo, verapamil reduced the weekly number of anginal episodes from 4.54 .+-. 5.03 to 2.44 .+-. 3.30 (P < 0.05) and reduced nitroglycerin consumption from 3.46 .+-. 5.30 to 1.55 .+-. 2.89 tablets per week (P < 0.05). Of 26 patients who completed the single-blind dose titration, 16 were improved (> 1 min) at a dosage of 240 or 360 mg/day. No patient improved (> 1 min) on 480 mg/day who had not already improved on a lower dose, but side effects requiring reduction in dosage occurred in 7 patients receiving 480 mg of verapamil per day. Verapamil is an effective antianginal drug that appears most efficacious at a dose of 360 mg/day, but side effects are common at a dose of 480 mg/day.