Duration and extent of antianginal effects of a sustained-release formulation of nifedipine in angina

Twenty-four patients with chronic stable exertional angina pectoris were randomized in a double-blind, placebo-controlled, crossover trial to assess the efficacy and durability of a newly developed sustained-release formulation of nifedipine (nifedipine CC) in a single 40-mg oral dose. Symptom-limited graded treadmill exercise tests were performed just before and at 4, 7, and 24 h after a single administration of the drug or the placebo was given. Exercise tolerance at 4, 7, and 24 h after the drug were compared with the corresponding placebo values. Data could be analysed for 19 patients. Maximal exercise time time to the onset of angina and time to 1 mm ST segment depression were significantly greater at 4, 7, and 24 h after nifedipine CC than at baseline or with the corresponding placebo. The average maximal exercise time was significantly increased by 72, 76 and 37 s at 4, 7, and 24 h. Rate-pressure product at rest and at peak exercise showed significant changes only at 24 h compared with placebo (both P < 0.05). The maximal increase in exercise tolerance was most marked at 7 h after nifedipine CC at which time plasma drug concentration was 99.4 ± 14.0 ng.ml^-1. Thus, in patients with chronic stable exertional angina pectoris nifedipine CC showed a prolonged improvement in exercise tolerance up to 24 h after a single oral administration.