Antianginal efficacy of long-term nitrate therapy

Forty patients suffering from angiographically proven coronary artery disease with stable angina pectoris were subjected to a randomized, double-blind, placebo-controlled study. The patients were divided into three groups who for 28 days running were given 20, 40, or 60 mg ISDN respectively, in sustained-release form, three times a day, and one group which received a placebo. A bicycle exercise test was performed prior to and 1, 3, 5, and 8 h following drug administration. The acute study was repeated at 14 and 28 days after drug administration. Following acute administration of 20, 40, or 60 mg ISDN SR a significant reduction in ST-segment depression was observed; between the ISDN-treated groups and the placebo group the difference was significant. After 4 weeks of treatment the mean reduction in ST-segment depression was unchanged. There was a significant improvement in the frequency of anginal attacks in all the ISDN-treated groups after 4 weeks of treatment, but not change in the placebo group. Thus, no attenuation of the anti-ischemic and antianginal effect could be recorded. During acute administration there was a significant dose-dependent reduction in blood pressure at rest in the ISDN-treated groups as compared with the placebo group. After 4 weeks of treatment a considerable attenuation of the blood pressure reduction was noted in all the ISDN-treated groups. Heart rate and pressure-rate product did not reflect any uniform trend.