The use of calcium blockers in arterial hypertension is based on experimental evidence for an altered role of calcium (Ca++) in hypertensive vascular smooth muscle and enhanced vasodilatatory effects of these drugs in the hypertensive organism. Both verapamil and nifedipine reduce blood pressure acutely and on chronic administration. Acute administration results in reflex-activated increments of heart rate, plasma renin activity, and plasma catecholamines after nifedipine, whereas these effects are less conspicuous after verapamil. Acute diuretic, natriuretic, and uricosuric effects can be demonstrated. On repeated administration of nifedipine, a degree of tolerance develops and on long-term administration it may be necessary to combine it with a beta-adrenoceptor blocker and a diuretic. In animal experiments, calcium blockers have shown favorable effects on hypertensive cardiovascular structural changes, but such unique beneficial effects remain to be demonstrated in the human disease.
- Copyright © 1983 by American Heart Association