The effects, as monotherapy, of felodipine ER 10 mg o.m. and nifedipine SR 20 mg b.d. were compared in a double-blind, randomized, placebo-controlled, three-way cross-over trial in 43 patients with stable exercise-induced angina pectoris. The exercise tests were performed at the end of dosage interval (i.e. 24 h after felodipine ER, 12 h after nifedipine SR) and at the expected peak time of 3 h post dose.Felodipine and nifedipine improved exercise duration by 66 and 50 s, respectively, (P<0.001) compared with placebo at the end of the dosing interval. Time to the end of exercise showed no statistically significant difference between the two calcium antagonists. The onset of anginal pain and time to 1 mm ST depression were significantly more delayed by felodipine ER than nifedipine SR (22 s and 19 s, respectively, P<0.05). Both felodipine and nifedipine decreased the pain score and rate pressure product at the highest comparable work load. Overall tolerability was good for both drugs.