To evaluate whether
bepridil once a day provides effective antianginal
therapy during extended use, a placebo-controlled withdrawal study was conducted in 33 patients with
chronic stable angina. Each patient studied had previously had a favorable response to short-term administration of
bepridil and had been taking the
drug once daily for greater than or equal to 9 months of continuous use. Patients were then randomly assigned to receive either continued
bepridil or a placebo substitution once daily during a 4-week, double-blind, parallel-group comparison. Dosage for the
bepridil group was constantly maintained for each patient at a level observed to be clinically effective. The study consisted of a comparison of angina frequency and
nitroglycerin tablet consumption obtained from patient diaries and results from maximal-graded multistage treadmill tests. Patients randomized to continue receiving
bepridil remained stable in terms of angina frequency and exercise performance. Discontinuation of long-term
bepridil significantly increased angina frequency and
nitroglycerin tablet consumption and reduced exercise capacity. Four patients (24%), all receiving placebo treatment, had increases in angina frequency and had the study terminated.
Bepridil was reinstituted in these patients with resolution of symptoms and no untoward effects. The results of this placebo-controlled, double-blind, randomized study confirm that
bepridil continues to provide antianginal benefit during long-term administration.