The cardiovascular effects of a newly developed nicotinamide derivative, N-(2-hydroxyethyl)nicotinamide nitrate (SG-75), were examined in anesthetized, open-chest or closed-chest dogs and compared with those of nitroglycerin and diltiazem. When administered intra-arterially, SG-75 (0.003-1 mg) increased coronary, renal, mesenteric, and femoral blood flows in a dose-dependent fashion, without affecting systemic blood pressure or cardiac function. The coronary vasodilator response to SG-75 was not influenced by intra-arterial administration of propranolol, atropine, diphenhydramine, or dipyridamole. SG-75 (0.03-1 mg/kg) administered intravenously decreased systemic blood pressure and peripheral (coronary, renal, mesenteric, and femoral) vascular resistance and increased peripheral blood flow in a dose-dependent manner. In doses of 0.03-0.3 mg/kg, this drug did not significantly affect pulse pressure, heart rate, right atrial pressure, aortic blood flow, left ventricular (LV) pressure, LV dP/dt, or myocardial oxygen consumption. The results indicate the SG-75 has desirable characteristics as an antianginal agent.