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 in urine at 18%. Other metabolites included 6α‐OH finasteride and its glucuronide conjugate, as well as the glucuronide conjugate of the acid metabolite.