Minoxidil increases aldosterone metabolic clearance in hypertensive patients.

It has been shown that despite an effect of minoxidil to increase PRA, plasma levels of aldosterone do not change. We observed similar findings in seven hypertensive patients undergoing treatment with minoxidil; PRA activity increased markedly, whereas the plasma aldosterone concentration showed no consistent change. The aldosterone MCRs in these patients increased by 41% in response to minoxidil, from 1110 +/- 91 to 1570 +/- 180 (SEM) liters/day; this appeared to explain why plasma aldosterone levels did not increase in parallel with renin activity. Hepatic blood flow (estimated from the clearance of indocyanine green) in a group of patients receiving minoxidil was greater than that in an otherwise comparable group (P less than 0.02). This increase in hepatic perfusion may, at least in part, have accounted for the increase in aldosterone MCR.