Isosorbide-5-mononitrate in angina pectoris: plasma concentrations and duration of effects after acute therapy.

In a double-blind, randomized, crossover study, the duration of effects of single oral doses of 20 and 40 mg isosorbide-5-mononitrate (IS-5MN) and matching placebo were studied in 12 male patients with angina pectoris. Plasma IS-5MN concentrations (mean +/- SD) 2 and 6 hours after administration were 300 +/- 60 and 144 +/- 43 ng/ml after 20 mg IS-5MN and 551 +/- 191 and 376 +/- 129 ng/ml after 40 mg IS-5MN. Exercise time to the onset of angina 2 and 6 hours after administration increased after 20 mg IS-5MN (5.88 +/- 1.85; P less than 0.001 and 5.08 +/- 1.97 minutes; P less than 0.002) and 40 mg IS-5MN (6.17 +/- 1.88; P less than 0.001 and 5.78 +/- 1.72 minutes; P less than 0.001) in comparison to placebo (4.57 +/- 1.22 and 4.15 +/- 1.22 minutes). Similarly, total exercise duration increased at 2 (P less than 0.001) and 6 hours (P less than 0.002) after both doses of IS-5MN. Compared with placebo, ECG ST segment depression during exercise was less (P less than 0.05) 2 hours after both doses of IS-5MN. Thus single oral doses of 20 and 40 mg IS-5MN exert antianginal and anti-ischemic effects for at least up to 6 hours.