Vasospastic (Prinzmetal's or variant) angina. Chronic stable angina without vasospasm, including angina due to increased effort (especially in clients who cannot take beta blockers or nitrates or who remain symptomatic following clinical doses of these drugs). Essential hypertension (sustained-release only). Investigational: PO, sublingually, or chewed in hypertensive emergencies. Also prophylaxis of migraine headaches, primary pulmonary hypertension, severe pregnancy-associated hypertension, esophageal diseases, Raynaud's phenomenon, CHF, asthma, premature labor, biliary and renal colic, and cardiomyopathy. To prevent strokes and to decrease the risk of CHF in geriatric hypertensives.