ANTIANGINAL AGENTS

ANTIANGINAL AGENTS are used to relieve angina pectoris, an intense pain due to cardiac ischaemia, which is especially pronounced in exercise angina. The disease state often results from atheroma; a degeneration of the lining of the arteries of the heart due to build-up of fatty deposits. The objective is to relieve the heart of work, and to prevent spasm or to dilate coronary arteries. Unloading can be achieved by stopping exercise, preventing the speeding of the heart and by dilating the coronary arteries.

Beta-blockers, by inhibiting the effect of adrenaline and noradrenaline on the heart, prevent the normal increase in heart rate, and are very effective in preventing exercise angina. Examples of beta-blockers used for this purpose include acebutolol, atenolol, metoprolol, nadolol, oxprenolol, pindolol, propranolol, sotalol and timolol. See β-ADRENOCEPTOR ANTAGONISTS.

Many VASODILATORS act directly to relax vascular smooth muscle, so dilating blood vessels and thereby increasing blood flow (see SMOOTH MUSCLE RELAXANTS). For the acute treatment of anginal pain (and to a lesser extent in preventing angina attacks) the nitrates are widely used, e.g. glyceryl trinitrate, isosorbide dinitrate, isosorbide mononitrate and pentaerythritol tetranitrate. CALCIUM-CHANNEL BLOCKERS have more recently been introduced for the treatment of angina. They dilate the coronary arteries and peripheral small arteries, which helps reduce load on the heart. Examples include amlodipine, diltiazem, nicardipine, nifedipine and verapamil.