Calcium antagonists in hypertension.
Calcium antagonists are potent arterial vasodilators with no long-term effect on sympathetic reflex activity or sodium and volume retention. This favourable haemodynamic profile makes them suitable for monotherapy of hypertension, where they act to reduce an enhanced, calcium-influx-dependent vasoconstrictor mechanism which may be brought about by altered smooth-muscle cation handling and increased intracellular concentrations of free calcium. Clinical studies have proved the efficacy, safety and acceptability of calcium antagonists alone or in combination with other drugs in uncomplicated hypertension; calcium antagonists are particularly effective in older patients, those with low renin levels and, possibly, black patients. These properties and the efficacy of calcium antagonists in the treatment of severe and accelerated hypertension or hypertensive emergencies make them a valuable addition to the drugs already available for the treatment of hypertension.