Nitrate therapy for angina pectoris. Current concepts about mechanism of action and evaluation of currently available preparations.

Nitrates are presently used in the therapy for angina pectoris. They have both direct coronary vascular and indirect systemic effects; each appears to contribute to their anti-anginal efficacy. The various nitrate preparations, including the newer preparations recently made clinically available, have varying utilities in the relief of acute ischemic pain or for anginal prophylaxis. Nitrate tolerance and dependence are proved phenomena, yet their impact on the clinical usage of nitrates is not clearly defined. The utility of nitrates, including intravenous nitroglycerin, in the treatment of unstable angina and vasospastic angina is well documented. Their efficacy compared with that of calcium channel blockers is still being investigated. The reported adverse effects of nitrates are few, despite their many years of usage in clinical medicine.