Finasteride

Finasteride was a 5α-reductase type II inhibitor used for treating benign prostatic hyperplasia and pattern baldness. In studies with healthy human volunteers, after oral administration, 39% of the [14C]-finasteride dose was recovered in urine and 57% in feces, with less than 1% excreted unchanged. The major circulating metabolite was ω-hydroxy finasteride, accounting for 12% of total radioactivity, while finasteride-ω-oic acid was the primary metabolite found in urine, making up 18%. Other metabolites included 6α-OH finasteride and its glucuronide conjugate, as well as the glucuronide conjugate of the acid metabolite.