[Extent of therapeutic effect and duration of 1 capsule of 120 mg isosorbide dinitrate in a slow release form].

In this randomised, double-blind placebo-controlled crossover study we investigated the efficacy of 120 mg isosorbide dinitrate s.r. 12 h after application in comparison to 2 and 6 h in 18 patients with angiographically proven coronary artery disease, stable exercise-induced angina and reproducible ST-segment depression. Bicycle ergometry was performed before, 2, 6 and 12 h after medication and nitrate plasma levels were drawn before each exercise test. After 2 h, the exercise-induced ST-segment depression in comparison to placebo was reduced from 2.3 mm +/- 0.8 to 0.7 +/- 0.5, after 6 h to 1.0 mm +/- 0.8) and after 12 h to 1.9 mm +/- 0.8 (p less than 0.01). 82% of the patients suffering from angina on the control exercise test before medication were free of symptoms 2 and 6 h after ISDN 120 mg s. r., but showed angina again after 12 h. In comparison to the plasma levels 2 h after ingestion, the concentrations in plasma after 12 h were much lower for ISDN, equal for IS-2-MN, and more than double for IS-5-MN. Thus, 12 h after ingestion of 120 mg ISDN s.r. there is still a significant reduction of ST-segment depression. This 12-h benefit is 40% od the maximum effect.