Parenteral nitroglycerin: clinical usefulness and limitations.

It would appear that nitroglycerin, which has been the time-honored therapy for angina pectoris, has a much broader therapeutic scope. Since the Food and Drug Administration has only recently released intravenous nitroglycerin for general clinical use, other clinical applications may develop in the future. Intravenous nitroglycerin appears to provide predictable and rapid lowering of left ventricular filling pressure and mean arterial pressure in patients with ischemic heart disease. The ability to increase cardiac output appears to be greatest in those patients with severe left ventricular failure. However, anti-ischemic effects are evident in all hemodynamic subgroups. Compared with sodium nitroprusside, nitroglycerin appears to have more favorable effects on intercoronary collateral flow, pulmonary artery pressure, and intrapulmonary shunting. In the perioperative setting, nitroglycerin appears to be as effective an afterload-lowering agent as nitroprusside in the majority of patients. In view of its more favorable effects on coronary collateral resistance, nitroglycerin may be preferable to nitroprusside for many such afterload-lowering applications, especially in patients with significant obstructive coronary disease. With greater clinical use, intravenous nitroglycerin will undoubtedly prove to be a valuable new tool for the management of patients with ischemic heart disease.