[Efficacy and duration of action of isosorbide-5-mononitrate in the treatment of stable angina of effort. Comparison with sustained-release isosorbide dinitrate].

A new compound, Isosorbide-5-mononitrate (IS-5-MN; 40 mg orally), was compared with sustained-release Isosorbide dinitrate (SRDI; 40 mg orally) in 18 patients with chronic exercise-induced angina pectoris. The patients were studied in a randomized placebo-controlled single-blind trial. Multistage bicycle test with computer-assisted electrocardiographic analysis was performed before, 60-90, 240 and 360 minutes after treatment administration. Both drugs significantly and comparably prolonged exercise time (p less than 0.01) and time to development of 1 mm ST-segment depression (p less than 0.01) at the 3 times of study. At the highest common level of work, ST-segment depression and its integral were significantly reduced by both IS-5-MN and SRDI compared to placebo (p less than 0.01); conversely, the peak ST-segment depression was unaffected. Compared to placebo, a significant increment in maximal heart rate/systolic blood pressure was observed after drug administration. It is concluded that 40 mg of orally administered IS-5-MN is effective during at least 6 hours and that its therapeutic action is comparable to that of SRDI.