[Dose-effect relationship of isosorbide dinitrate in the treatment of angina pectoris (author's transl)].

Fifteen males with angiographic evidence of coronary heart disease and stable, exercise-induced angina pectoris were given placebo or isosorbide dinitrate (ISDN) in a dialy dose of 30 mg, 120 mg, 240 mg and 480 mg in a randomized single-blind trial. The daily doses were given as a single oral dose of 5 mg, 20 mg, 40 mg and 80 mg tablets. Each dose and placebo was given for seven days. On the seventh day an exercise ECG of standardized level and duration of exercise was recorded. The ischaemia response in the ECG revealed a dose-dependent reduction by 28% (5 mg ISDN), 43% (20 mg), 60% (40 mg) and 73% (80 mg). The number of anginal attacks similarly fell parallel to dose. Plasma level of ISDN and the mononitrates, measured one and four hours after drug intake, rose almost linearly in relation to dose. Oral ISDN thus has a dose-dependent effect on the frequency of angina and ischaemia parameters during ergometric exercise. The protracted anti-anginal effect of ISDN is largely due to its metabolites. At high doses there is presumably an added effect of the high blood level of the basic substance.U