Amlodipine in chronic stable angina: results of a multicenter double-blind crossover trial

The efficacy and safety of amlodipine, 10 mg, a new long-acting calcium antagonist, was compared with placebo in 103 patients with stable angina pectoris in a multicenter double-blind crossover study. The trial consisted of an initial 2-week single-blind placebo period followed by a first period of 4 weeks of double-blind therapy, which was followed by a 1 week washout period and then a second 4-week double-blind period after treatments were crossed over. Twenty-four-hour Holter electrocardiographic monitoring was carried out in 12 patients at three centers. In the first double-blind period amlodipine produced a significantly greater increase in symptom-limited exercise duration (amlodipine 478.5 to 520.6 vs placebo 484.6 to 485.2 seconds; change +8.8% vs +0.1%, respectively; p = 0.0004) and total work (amldipine 2426 to 2984 vs placebo 2505 to 2548 kilopondmeters; change +24% vs +1.7%, respectively; p = 0.0006) and a decrease in angina attack frequency (from 3 to 1 per week; p = 0.016) and nitroglycerin consumption (from 2 to 0.5 tablets/wk; p = 0.01) compared with placebo. Holter monitoring revealed significant reductions in numbers (amlodipine 4.65 to 2.22 vs placebo 1.84 to 1.54; change -52% vs +84%, respectively; p = 0.06), absolute total area (amlodipine 87.66 to 11.43 vs placebo 5.76 to 35.24; change -87% vs +513%, respectively; p = 0.02), and duration (amlodipine 12.29 to 2.95 vs 1.66 to 7.74 seconds; change -76% vs +367%, respectively; p = 0.008) of ST-segment depressions after treatment with amlodipine compared with placebo. After the treatments were crossed over changes continued to favor amlodipine.(ABSTRACT TRUNCATED AT 250 WORDS)