The efficacy and safety of high‐dose verapamil and diltiazem in the long‐term treatment of stable exertional angina

Abstract

Summary:The efficacy and safety of highdose verapamil (480 mg/day) and diltiazem therapy (360 mg/day) were compared in separate cohorts of 26 and 20 patients, respectively. All patients had stable exertional angina and underwent an initial 6-week double-blind, placebocontrolled, randomized phase followed by a 12-month open-label period. Angina attacks were reduced by veraparml(6.3 f7.5 to 2.5 f4.1 attacks per week, p <0.001) and by diltiazem (9.2f7.5 to 3.0f3.1 attacks per week, p <0.001), while treadmill time increased with both verapamil (372f132 to 444+108 s, p<O.OOl) and diltiazern (412*175 to536f164s, p<O.OOl)duringtheshortterm study. Both agents continued to show similar salutory effects at the end of one year. The beneficial effects of both drugs appeared to be related in part to a reduction of the rate-pressure product during submaximal exercise (12% by verapamil, 7% by diltiazem, both p<O.O5). Adverse effects were few and consisted primarily of mild constipation in six patients taking verapamil, and pedal edema and transient flushing in 2 patients each using diltiazem. Thus, high-dose verapamil and diltiazem have similar beneficial effects and are safe for the long-term treatment of effort-related angina pectoris.

Diltiazem

“…Apart from that conducted by Weiner et al (1984), trials comparing diltiazem with other calcium antagonists in patients with effort angina have been of relatively short duration (table VII). Several double-blind studies have shown diltiazem to be more effective than nifedipine in reducing the frequency of anginal attacks and increasing the number of pain-free days (Frishman et al 1988;Klinke et al 1988;Pagliano 1985).…”

Calcium Antagonism—with Special Reference to Diltiazem

“…Comparative studies of diltiazem, nifedipine and verapamil are few but in those that have been undertaken the efficacy of all three compounds has been found to be comparable (54). When comparing single doses of diltiazem, nifedipine and propranolol, however, diltiazem has been shown to improve exercise tolerance over a longer period of time (55).…”