Dutasteride: a potent dual inhibitor of 5-alpha-reductase for benign prostatic hyperplasia.

Dutasteride is a 5alpha-reductase inhibitor that inhibits both types 1 and 2 isozymes of 5alpha-reductase, the enzyme responsible for converting testosterone to dihydrotestosterone in the prostate and other tissues. Dihydrotestosterone is the primary cause of prostate growth and has been proven to play a key role in the development and progression of benign prostatic hyperplasia. Dutasteride has been investigated in three multicenter studies involving 4325 men aged 50 years and above with benign prostatic hyperplasia. Data from these two-year, placebo-controlled studies demonstrated that dutasteride 0.5 mg once daily reduced the risk of both acute urinary retention and the need for benign prostatic hyperplasia-related surgical intervention, improved benign prostatic hyperplasia-related symptoms, decreased prostate volume and increased maximum urinary flow rates with a low incidence of generally mild to moderate adverse events.