Calcium antagonism--a new concept for treating essential hypertension

Research on calcium antagonists has been prompted by the observation that the powerful vasodilatory effect of verapamil, as well as other calcium antagonists, is enhanced in hypertensive patients. Increased vascular resistance, seen in most types of hypertension, is determined by the intracellular free calcium concentration. The finding of an increased vascular responsiveness to calcium-channel blockade and the direct relation between the degree of antihypertensive response and the height of pretreatment blood pressure indicate abnormal intracellular calcium handling in patients with essential hypertension. This is supported by the observation that the intracellular free calcium concentration was significantly increased in patients with essential hypertension compared with normotensive subjects. The decrease in blood pressure with calcium antagonists was directly correlated with the patient's age and inversely with the pretreatment plasma renin activity. There was comparable antihypertensive efficacy among verapamil, nifedipine and nitrendipine. Increased understanding of pathophysiologic mechanisms in essential hypertension and pharmacotherapeutic studies have led to a new strategy for treatment of high blood pressure--in which calcium antagonists may be used, at least in part, as alternatives to diuretic drugs primarily in older and low renin patients with essential hypertension.