COMPARATIVE-STUDY OF ANTIANGINAL AND ANTIISCHEMIC EFFECTS OF CALCIUM-ANTAGONISTS BEPRIDIL AND DILTIAZEM IN PATIENTS WITH EFFORT ANGINA

Bepridil (300 mg/day) and diltiazem (360 mg/day) were compared in 15 patients (pts) with ischemic heart disease and reproducible exercise induced ischemia on veloergometer. The study had single blind randomized crossover design with 4 weeks of active drugs and placebo periods (1 week each) before, between and after active treatments. Bepridil was effective in 2/3 of patients. Both drugs significantly increased mean exercise duration from 437+/-19 sec after first placebo period to 592+/-40 sec (p<0.004) and 660+/-36.3 sec (p=0.001) at the end of week 4 of bepridil and diltiazem, respectively. Dynamics of mean work loads in watts followed that of exercise duration on both drugs. Bepridil prolonged QT interval from 0.42+/-0.01 sec to a maximum of 0.46+/-0.02 sec (p=0.003) after week 1 with a mean increment of 0,04 sec. In 1 patient it was stopped prematurely because of QT prolongation. Increase in QT duration on deltiazem was less pronounced. Thus bepridil 300 mg/day is relatively safe and almost as effective as diltiasem 360 mg/day for alleviation of exercise induced angina and ischemia. But control of QT duration is desirable at least after first week of therapy with bepridil.