Place of calcium antagonists in the treatment of hypertension.

The reduction of transmembraneous calcium influx into vascular smooth muscle cells by calcium antagonists leads to a reduction of tension development and vascular tone. Calcium antagonists reduce forearm vascular resistance dose dependently and this effect can be successfully utilized for the treatment of essential hypertension where they act by reducing increased peripheral vascular resistance thereby normalizing the main haemodynamic derangement of hypertensive patients. In contrast to other direct acting vasodilators the antihypertensive effect is not accompanied by sympathetic reflex activation or volume retention making it feasible to use calcium antagonists as monotherapy for hypertensive patients. In view of the well documented efficacy, tolerability and an excellent safety profile calcium antagonists have become drugs of choice for treatment of hypertension in many patients. Although all calcium antagonists have been shown to lower blood pressure they differ with respect to their vasodilating potency and their negative inotropic effects. The development of dihydropyridine calcium antagonists which are potent arterial vasodilators but have little if any negative inotropic effects at clinically used dosages further improves the safety profile of calcium antagonists, particularly when used in hypertensive patients with impaired left ventricular function.