Efficacy of incremental doses of tiapamil on exercise performance in patients with chronic stable angina pectoris.

Ten patients with chronic stable angina were treated with 4 incremental doses of tiapamil (200 mg, 400 mg, 600 mg and 800 mg) in a double-blind, placebo-controlled study. Treadmill exercise electrocardiograms were performed before and after single oral doses of tiapamil. A dose-dependent increase in exercise duration occurred after tiapamil with significant improvement after tiapamil 600 mg and 800 mg. Mean exercise duration increased from 327 +/- 41 seconds (control) to 399 +/- 49 seconds (P less than 0.01) after tiapamil 600 mg and from 314 +/- 39 seconds (control) to 416 +/- 49 seconds after tiapamil 800 mg, P less than 0.001. There was an associated improvement in mean exercise time to onset of 1 mm ST-segment depression from 240 +/- 41 seconds (control) to 300 +/- 48 seconds in 10 patients after tiapamil 600 mg, (P less than 0.02) and from 206 +/- 35 seconds (control) to 272 +/- 51 seconds in 9 patients after tiapamil 800 mg, P less than 0.01. Two patients were free of angina and 1 patient normalized his ST-segments after tiapamil 800 mg. Dose-dependent side-effects were mild and tolerable. Tiapamil is safe and highly effective in improving exercise tolerance and relieving myocardial ischaemia in patients with chronic stable angina.