[Comparative evaluation of 3 calcium antagonist drugs in patients with stable angina of effort. Double-blind placebo-controlled randomized study].

A study was undertaken in order to compare the effects of Diltiazem, Nifedipine and Verapamil on 11 male adults (aged 44 to 70 yrs: mean age 60 yrs) affected by effort angina with a stable exercise threshold. The study was carried out according to a 4 week double-blind randomized protocol. Diltiazem (300 mg/die), Nifedipine (50 mg/die), Verapamil (400 mg/die) and placebo were administered each for 7 day periods. An ergometric test was performed on the last of each therapeutic cycle in order to evaluate the effects of the treatments. The three active drugs globally provoked an increased tolerance to physical effort with respect to placebo (p less than 0.01); no significant differences, as regards physical performance, could be detected among the three drugs. Treatment with Nifedipine significantly increased heart rate at rest (p less than 0.05), under submaximal (p less than 0.05) and maximal load (p less than 0.05), with respect to treatment with Diltiazem and Verapamil. Systolic and diastolic arterial blood pressure did not vary significantly with any of the three drugs. Rate pressure product under submaximal load (p less than 0.05) and at the end of the exercise (p less than 0.05) was higher with Nifedipine than with the other two drugs. These results show that patient response to Nifedipine is different from that to Verapamil and Diltiazem and suggest that the three drugs exert their anti ischemic effect through different mechanisms. The evaluation of individual response revealed that only one patient showed no increased tolerance to physical effort with any of the drugs.(ABSTRACT TRUNCATED AT 250 WORDS)