Effect of swallowed isosorbide dinitrate on blood pressure, heart rate and exercise capacity in patients with coronary artery disease.

Blood pressures and heart rates were measured with the patients supine and standing after a placebo and small (5 to 10 mg) and large (10 to 30 mg) doses of isosorbide dinitrate were given orally in double-blind fashion to six patients. Compared to the findings after the placebo, the blood pressure level fell and the heart rate increased after the ingestion of isosorbide dinitrate. The changes were more striking with the patients standing than with them supine, and the larger dose of the drug produced greater changes than the smaller dose. The hemodynamic effects were usually apparent at 15 minutes, peaked between 30 and 120 minutes, and were still present at 240 minutes. Two hours after swallowing a 7.5 to 20 mg dose of isosorbide dinitrate or placebo, administered in random fashion, 10 patients with coronary artery disease and angina pectoris underwent graded, treadmill, exercise testing designed to provoke angina only after 3 minutes or more. Nine of them exercised longer and achieved higher maximal heart rates after taking the isosorbide dinitrate. Thus, in man, swallowed isosorbide dinitrate has a dose-related, "long-acting," pharmacologic effect, and when tested by properly designed protocols, it improves exercise capacity. However, because the problems of nitrate tolerance and dependence have not been resolved, the place of oral nitrates in the management of patients with angina pectoris remains uncertain.

RCT Entities:   Population Interventions Outcomes