Minoxidil selectively improves peritoneal ultrafiltration.

This cross-over randomized clinical trial was carried out to evaluate the effects of intraperitoneal (i.p.) administration of minoxidil on fluid removal and solute clearance during peritoneal dialysis. Twenty-one patients with endstage renal disease, awaiting enrollment in chronic hemodialysis therapy, were randomly allocated to receive i.p. minoxidil either in the first or the last nine cycles of a 24-cycle peritoneal dialysis session. Cycle-to-cycle data on fluid balance, blood pressure, and adverse effects of the drug were obtained. The dialysis fluid recovered in cycles 3, 6, 9, 18, 21, and 24 was analyzed, together with plasma, for creatinine, urea nitrogen, and protein content. The mean excess fluid volume collected in minoxidil cycles was 1123.8 +/- 1119 mL versus 145.2 +/- 743.6 mL in the minoxidil-free cycles (p = 0.004). The mean creatinine clearance, urea nitrogen clearance, and protein losses were comparable in minoxidil cycles and the minoxidil-free cycles. Six patients developed hypotension during the minoxidil cycles, corrected by normal saline, but no other important side effects were noted. It is concluded that i.p. minoxidil selectively increases ultrafiltration without influencing solute clearance in peritoneal dialysis.