Calcium antagonists and the kidney.

During the past decade, attention has focused on the effects of calcium antagonists on renal function. Recent studies using diverse video microscopic techniques, including the isolated perfused hydronephrotic rat kidney model, which permits direct visualization of afferent and efferent arterioles, have demonstrated that calcium antagonists acutely antagonize pre-glomerular vasoconstriction. In contrast, most studies suggest that the efferent arteriole appears to be refractory to the vasodilatory effects of these agents. Although the clinical implications of such observations have not been fully delineated, the results of recent studies indicate that calcium antagonists exert salutary effects on renal function in clinical settings characterized by impaired renal hemodynamics, including transplant-associated acute renal insufficiency and possibly cyclosporin nephrotoxicity. Evidence has accrued suggesting that calcium antagonists may also be protective against acute radiocontrast-induced nephrotoxicity. The renal hemodynamic and natriuretic effects of calcium antagonists command their use as antihypertensive agents in the management of essential hypertension, and transplant-associated hypertension.