Dose-response relation of antianginal activity of isosorbide dinitrate

Eleven men with angiographic evidence of coronary heart disease and stable, exercise-induced angina pectoris were given placebo (P) or isosorbide dinitrate (ISDN) in a daily dose of 30, 120, 240 or 480 mg, in a randomized single-blind trial. The daily doses were administered 6 times a day as single oral doses of 5, 20, 40 and 80 mg. Each dose or placebo was given for 7 days. Before therapy was begun, and on the seventh day of each treatment period, an exercise ECG with standardized level and duration of exercise was recorded. Subsequently, a 4-week treatment period with 480 mg/day was carried out at the end of which another stress test was performed. The was followed by a final 2-week placebo period. The frequency of anginal attacks per week tended to decrease with increasing nitrate doses, but decreased significantly only after the highest dose (480 mg/day) compared with placebo. Continuation of therapy with 480 mg/day maintained the reduced rate of anginal attacks. The ischemic response, expressed as the sum of ST-segment depressions in the exercise ECG, revealed a dose-dependent reduction of 26% (30 mg/day), 39% (120 mg/day) (p less than 0.01), 63% (240 mg/day) (p less than 0.01) and 72% (480 mg/day) (p less than 0.01), respectively. At the end of the 4-week treatment period with 480 mg/day, antianginal efficacy was found to be moderately reduced, showing a 56% reduction of ischemic response compared to the placebo trial. The time of onset of angina during exercise testing was also delayed in relation to the dosage given.(ABSTRACT TRUNCATED AT 250 WORDS)