A multicentre, open, crossover study in 27 patients with exertional angina compared the efficacy of verapamil LP 120 mg twice a day (VP LP 120) with that of verapamil LI 120 mg 3 times a day (VP LI 120) by means of stress tests. The study procedure was as follows: 7-day selection period during which the patient received placebo, and two 21-day treatment periods by VP LI 120 or VP LP 120 according to the crossover principle. At the end of each treatment phase, a stress test was performed at the trough serum concentration for each substance. VP LP 120 mg and VP LI 120 mg both improved exercise capacity compared to placebo. Comparison of VP LP 120 and VP LI 120 did not reveal any significant difference for stress test parameters (total duration of effort: 12 +/- 3.2 min with placebo, 13.3 +/- 3.7 min for the VP LI phase, 13.9 +/- 3.2 min for the VP LP phase; % FMT reached: 87.2% +/- 7.2 for VP LI, 89% +/- 7.3 for VP LP; time to onset of significant ST depression: 10 min +/- 2.9 for VP LI, 11 min 3.6 for VP LP). The efficacy of VP LP 120 in exertional angina is therefore identical to that of VP LI 120, despite a reduction of the total dose and serum levels.