DOUBLE-BLIND RANDOMIZED MULTICENTER STUDY ON THE EFFICACY OF TRAPIDILVERSUS ISOSORBIDE DINITRATE IN STABLE ANGINA-PECTORIS

Background: Trapidil is an inhibitor of phosphodiesterase I-TV with re sulting positive lusitropic, vasodilating, and antiplatelet effects. H ypothesis: This study was undertaken to compare the antianginal effica cy of trapidil with that of isosorbide dinitrate (ISDN) in patients wi th stable angina pectoris. Methods: We studied 95 patients with stable angina pectoris who were randomized into a double-blind parallel grou p study with either oral trapidil or ISDN. After a 1-week run-in perio d and a 2-week wash-out phase, the patients received either trapidil 2 00 mg t.i.d. (n = 48) or ISDN 20 mg t.i.d. (n = 47) for 12 weeks. Al a ntianginal medication, except sublingual glyceryl trinitrate (GTN), wa s discontinued during the study. Patients underwent an exercise electr ocardiogram on an ergometer bicycle according to a modified Bruce prot ocol before and at 6 and 12 weeks during treatment. Results: The workl oad capacity increased from 583 +/- 281 W . min before treatment to 83 3 +/- 644 W . min after 12 weeks of treatment in the trapidil group (p < 0.01) and from 555 +/- 276 W . min to 827 +/- 361 W . min in the IS DN group (p < 0.01). The anginal attacks per week as well as the use o f GTN decreased significantly in both groups. After 12 weeks of therap y, the cumulative ST-segment depression during exercise decreased by 6 7% in the trapidil patients and by 23% in the ISDN patients. Compared with baseline, the double product at the 75 W level was reduced in bot h groups after 12 weeks of treatment. Blood pressure and heart rate at rest remained nearly unchanged. Overall, no statistical difference wa s found between the two study groups. The tolerability was good. Concl usion: Oral trapidil therapy is safe and effective in stable angina pe ctoris and is equivalent to standard therapy with ISDN.