Transient renal effects of sildenafil in male kidney transplant recipients

Sildenafil (Viagra) improves erection by sustaining Guanosine 3', 5'-cyclic monophosphate (cGMP)-mediated smooth muscle relaxation in the corpus cavernosum. It also induces systemic vasodilation, resulting in a minor decrease in blood pressure. We evaluated the effect of one dose of sildenafil on graft function and hemodynamics in impotent male transplant recipients. Two sets of combined lithium, inulin, and p-amino hippurate clearance studies were conducted, with and without sildenafil (100 mg orally) in 11 male kidney transplant recipients (KTRs). Sildenafil increased glomerular filtration rate by 14+/-4 from the baseline value of 55+/-7 ml x min(-1) x 1.73 m2(-1) (P