Interim report of multicenter double-blind, placebo-controlled studies of nifedipine in chronic stable angina

Preliminary results from multicenter double-blind placebo-controlled studies involving crossover and parallel designs were analyzed in 32 and 34 patients with stable angina pectoris entered respectively into the two protocols. The frequency of anginal attacks and the intake of nitroglycerin were decreased about 50 percent in patients receiving nifedipine, and the difference from those on placebo was statistically significant. Similarly, exercise tolerance was significantly increased with nifedipine, as evidenced by several variables, and the degree of ischemia was believed decreased, as reflected by lesser ST segment depression at peak exercise. The heart rate-blood pressure product, an approximation of myocardial oxygen consumption, was slightly but significantly decreased at equivalent workloads, but was not significantly different from placebo at the onset of angina or at maximal exercise. Adverse reactions to nifedipine, although frequent, were generally benign and usually responded to dose adjustment or improved spontaneously. These results suggest that the calcium antagonist nifedipine is effective and safe in the treatment of chronic stable angina.