[Calcium antagonists: an antihypertensive alternative]

From a pathophysiological point of view, antihypertensive therapy with a vasodilator is rational. However, since traditional vasodilators, such as hydralazine, may cause retention of sodium and water, tachycardia and excessive stimulation of the renin-angiotensin-aldosterone system, they are not suitable for monotherapy. The Ca-antagonists include a number of drugs with quite different chemical structures. Ca-antagonists are powerful antihypertensive agents. This effect is due primarily to vasodilation caused by the interference with the excitation-contraction coupling in peripheral resistance vessels. All Ca-antagonists possess a natriuretic effect which apparently counteracts the sodium and water retention that vasodilation per se entails. Ca-antagonists cause no (verapamil) or a transient tachycardia (dihydropyridines) and they only cause a moderate and transient increase in plasma concentrations of renin and angiotensin II, whereas plasma aldosterone concentration is unaffected. Ca-antagonists have no metabolic side effects and in general the frequency of side effects is relatively low. Therefore, it is suggested that Ca-antagonists should be considered as possible first-choice agents along with diuretics, beta-blockers and angiotensin converting-enzyme inhibitors.