Increased Aldosterone Metabolic Clearance in Hypertensive Patients Treated with Minoxidil

Since minoxidil was previously shown to raise plasma renin activity (PRA) but not the plasma aldosterone concentration (PAC), the effect of minoxidil on the rate of aldosterone metabolic clearance was studied. After the addition of minoxidil to the antihypertensive regimen of 7 hypertensive patients, the aldosterone metabolic clearance rate increased from 1,110 +/- 91 to 1,570 +/- 180 liters/day (p less than 0.01), an overall increase of 41%. Hepatic blood flow, estimated from the clearance from plasma of indocyanine green, was increased in a group of minoxidil-treated patients compared to a comparable group not treated with minoxidil (p less than 0.01). Thus, although minoxidil induces an increase in PRA, PAC does not change, since aldosterone metabolic clearance increases. Minoxidil increased hepatic blood flow, and it was probably by this mechanism that the drug accelerated the rate of aldosterone clearance.