Finasteride is an anti-androgen agent used to treat benign prostatic hyperplasia and male pattern baldness. Some of the brand names finasteride is sold under include Proscar, Fincar, Propecia, Finpecia, Finast, Finax, Finara, Finalo and Prosteride.

How does it work?

Finasteride works by inhibiting type II 5-alpha reductase, the enzyme that converts testosterone to dihydrotestosterone (DHT). This converted form of testosterone stimulates development of the penis, testes and scrotum, as well as other male sexual characteristics such as body hair and pubic hair. DHT also promotes growth of the prostate.

Approval and use

In 1992, finasteride 5 mg per day was approved by the U.S. Food and Drug Administration (FDA) as a treatment for benign prostatic hyperplasia. The agent was marketed by Merck under the name Proscar. Patients need to allow at least 6 months for the therapeutic effects to be determined. Symptoms that may improve include difficulty urinating, increased urination frequency and decreased urinary flow. If the therapy is discontinued, symptoms will return within around 6 to 8 months.

In 1997, finasteride 1 mg per day was approved by the FDA as a treatment for male pattern baldness and this time the agent was market by Merck as Propecia. Finasteride 1 mg per day was shown to benefit men with mild to moderate hair loss in a five-year study. Two thirds of the men who took the medication on a daily basis saw some regrowth of their hair, while those who did not take the medication experienced further hair loss. Analysis showed that for all five years of the study, the average hair count remained above baseline among the finasteride group and was increased compared to those who did not take the treatment. The medication is only effective for as long as it is used, with the therapeutic effects being lost within 6 to 12 months after discontinuation of the therapy.