Dutasteride

Overview
Dutasteride (marketed as Avodart, Avidart, Avolve, Duagen, Dutas, Dutagen, Duprost) is a 5-alpha-reductase inhibitor, a drug which inhibits the conversion of testosterone into dihydrotestosterone (DHT). It is used to treat conditions caused by DHT, such as benign prostatic hyperplasia (BPH).

Classification and Method of Action
Dutasteride belongs to a class of drugs called 5-alpha-reductase inhibitors, which block the action of the 5-alpha-reductase enzymes that convert testosterone into dihydrotestosterone (DHT). Finasteride also belongs to this group. Dutasteride inhibits both isoforms of 5-alpha reductase, while finasteride inhibits only one. But a clinical study done by GlaxoSmithKline, the EPICS trial, did not find dutasteride to be more effective than finasteride in treating BPH.

Uses
While dutasteride is officially approved to treat enlargement of the prostate gland. Clinical trials for dutasteride as a hair loss drug were undertaken, but called off in late 2002. The reason the trials were called off is not publicly known. Industry sources speculate that Avodart would have been seen as too similar to Propecia to have proved profitable as a hair loss treatment.

In December 2006, Avodart manufacturer GlaxoSmithKline embarked on a new Phase III, six month study in Korea to test the safety, tolerability and effectiveness of a once-daily dose of dutasteride (0.5mg) for the treatment of male pattern baldness in the vertex region of the scalp (types IIIv, IV and V on the Hamilton-Norwood scale). The future impact that this study will have on the FDA's approval or disapproval of Avodart for the treatment of male pattern baldness in the United States is yet to be determined.