In a randomized, double-blind, cross-over, multicenter study with a placebo run-in phase, the efficacy and safety of two oral formulations of
diltiazem, standard three or four times daily (t.i.d. or q.i.d.) and controlled release twice daily (b.i.d.), were compared in 49 patients with
stable angina pectoris. ST-segment depression at maximum exercise 12 h after
tablet intake was less frequently observed with
diltiazem controlled release than with standard
diltiazem (34 of 49, 69% vs. 43 of 49, 88%, p = 0.007). In patients with ST-segment depression after both treatments (n = 33), the average time to 1-mm ST-segment depression was 55.4 +/- 19.9 s longer with
diltiazem controlled release than with standard
diltiazem [476 +/- 195 vs. 422 +/- 163 s, p = 0.009; 95% confidence interval (CI) 14.8-96 s]. Reduction in mean number of anginal attacks and
nitroglycerin (NTG) intake was not significantly different between treatment with standard
diltiazem and
diltiazem controlled release. The incidence of side effects was low and not different between the two treatments. Both formulations are equally effective in reducing the number of anginal attacks and are well tolerated.
Diltiazem controlled release is more effective than standard
diltiazem in preventing
myocardial ischemia 12 h after
tablet intake. Thus,
diltiazem controlled release allows twice-daily intake frequency and may therefore be preferable to standard
diltiazem in treatment of
stable angina pectoris.