Pharmacology of the nitrates in angina pectoris

Abstract

Nitrate therapy is the oldest treatment modality for angina pectoris. In addition to sublingual nitroglycerin, longer-acting preparations are available to provide angina prophylaxis. Nitrates work as venodilators and arterial dilators, and by these actions in patients with angina pectoris can reduce myocardial oxygen demands while maintaining or increasing coronary artery flow. On the cellular level, they may increase endothelial prostacyclin release to cause their vasodilating effects. Long-acting nitrates are available in sublingual, chewable, oral, buccal and topical forms. The topical forms include nitroglycerin paste and transcutaneous patches. Long-acting nitrates have a duration of action of 2 to 24 hours, depending on the preparation used. The transcutaneous patches, which provide the longest duration of activity, are being reexamined regarding long-term efficacy and drug tolerance. Nitrates are also available in an intravenous form and in a short-acting sublingual spray soon to be released. The safety of nitrates has been confirmed. Their hemodynamic and safety profiles allow them to be combined with calcium-channel blockers, beta-adrenergic blockers or both when trying to improve on the antianginal efficacy of single-drug therapy.