Renal Aspects of Certain Antihypertensive Agents

Abstract

Certain antihypertensive agents which have a direct action on vascular smooth muscle may alter renal function and thereby substantially reduce urine and electrolyte excretion. Comparisons of the renal effects of known antihypertensives were made with diazoxide, an analog of chlorothiazide, which effectively reduces arterial pressure in certain normotensive and hypertensive animals. Although this drug causes marked Na and water retention in animals and man, these effects are apparently not due solely to the reduction in arterial blood pressure. The exact mechanism of the antidiuretic activity is not known, but evidence indicates that diazoxide may modify water and electrolyte transport by a direct action on tubular sites or by some hemodynamic action not directly related to changes in arterial pressure. The findings also suggest that a separation of the antihypertensive and diuretic effects of benzothiadiazines were achieved. However, it appears that the dissociation of diuretic from antihypertensive activity with these drugs results in compounds with marked water and Na retaining properties.