Chapter 23: Antianginal Drugs

Angina develops when coronary blood flow becomes inadequate to supply the oxygen demands of heart muscle tissue, leading to ischemia and characteristic chest discomfort. The chapter establishes the pathophysiological foundation by discussing ischemic heart disease, atherosclerotic narrowing of coronary vessels, and the clinical distinction among three angina presentations: chronic stable angina triggered by exertion, unstable angina signaling acute coronary compromise, and vasospastic angina resulting from coronary artery constriction. Three primary drug classes form the cornerstone of antianginal therapy. Nitrates including nitroglycerin and isosorbide derivatives work through vasodilation, reducing cardiac preload and afterload while preferentially redistributing oxygenated blood to ischemic myocardial regions. Beta blockers such as atenolol and metoprolol decrease heart rate and contractile force, thereby lowering myocardial oxygen demand and improving survival outcomes following myocardial infarction, though they are contraindicated in bradycardia, bronchospastic disease, and conduction disturbances. Calcium channel blockers including diltiazem, verapamil, and amlodipine produce vasodilation of coronary and systemic arteries while reducing afterload and contractility, proving particularly effective in vasospastic presentations and supraventricular arrhythmias. Ranolazine represents a newer agent that prolongs cardiac repolarization without altering heart rate or blood pressure, reserved for refractory angina unresponsive to conventional therapy. The chapter addresses adverse effects across all classes, including hypotension, reflex tachycardia, headache, peripheral edema, constipation, and bronchospasm, alongside critical contraindications such as nitrate administration with phosphodiesterase inhibitors due to profound hypotensive risk. Nursing management encompasses comprehensive pain assessment, hemodynamic monitoring via electrocardiography, appropriate nitroglycerin storage and administration technique, identification of drug tolerance development, and patient instruction regarding medication adherence, gradual dose adjustments, avoidance of abrupt beta blocker discontinuation, and dietary interactions with agents like calcium channel blockers.