ABSTRACT
A large number of compounds can be classified as vasodilators, and their mechanisms of action are diverse. Vasodilators cause relaxation of blood vessels and are therefore useful in the treatment of a variety of cardiovascular diseases in which blood flow in, or to, a particular organ is restricted and perfusion pressure is increased. They can relieve both the acute and chronic symptoms of these diseases, and even possibly their pathological progression. Among the direct vasodilators, the organic nitrates are of prime importance in therapy. This class of agents includes nitroglycerin, isosorbide dinitrate, nicorandil, and isosorbide-5-mononitrate (IS-5-MN). The four mononitrate vasodilators are geometric isomers, comprised of l–isoidide mononitrate, isosorbide-2-mononitrate, isomannide mononitrate, and IS-5-MN, which possess varying vasodilating potencies but none produces active metabolites. The angiotensin-converting enzyme catalyzes both the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, and the destruction of bradykinin, a potent vasodilator.
