Hair Loss & Restoration Article: Propecia, Proscar, Finasteride, Dutasteride, Avodart, 5-Alpha-Reductase Inhibitors as Hair Loss Treatments

5-Alpha-Reductase Inhibitors For Hair Loss

New 5-alpha-reductase Inhibitor to Be Available to Treat Benign Prostate Hypertrophy

Inhibition of the enzyme 5-alpha-reductase is a medical treatment with two applications: (1) treatment of benign prostate hypertrophy (swelling) in men, and (2) treatment of male-pattern hair loss (MPHL), otherwise known as androgenetic alopeciaor simply male pattern baldness. The enzyme 5-alpha-reductase is involved in the production of dihydrotestosterone (DHT), a form of the hormone testosterone that is associated with both male pattern hair loss and swelling of the prostate in men—especially older men. See About hair loss for more information on DHT and MPHL.

The oral medication finasteride, a selective inhibitor of Type II 5-alpha-reductase, is used under the commercial name Propeciato treat male pattern baldness, and under the commercial name Proscarto treat benign prostate hypertrophy in men. (See Nonsurgical hair loss treatment options for more information on finasteride. Propecia and Procar are products of the pharmaceutical firm Merck.

Scheduled for early 2003 release in the U.S. is a second-generation 5-alpha-reductase inhibitor approved by the FDA for use in treating benign prostate hypertrophy in men under the commercial name Avodart. The drug’s chemical name is dutasteride. It is a product of the pharmaceutical firm Glaxo SmithKline. Like Propecia and Proscar, Avodart will be available only by prescription.

According to information from Glaxo SmithKline, dutasteride inhibits both the Type I and Type II forms of 5-alpha-reductase. Before FDA approval for release in the U.S., dutasteride was investigated for safety and effectiveness in three two-year, multi-center, randomized, placebo-controlled clinical trials involving 4,325 men who were 50 years old or older and who had both symptoms and clinical evidence of benign prostate hypertrophy. Dutasteride was found to reduce DHT by more than 90%, according to a chief investigator involved in the trials. Drug effectiveness was noted in decrease of prostate swelling, and in the amount of prostate-specific antigen (PSA) in the blood. The drug was found to be generally well tolerated. Drug-related side effects in the first 6 months of the trials included impotence (4.7%), decreased sex drive (3.0%, breast tenderness or enlargement (0.5%), and ejaculation disorders (1.4%); most of the side effects were reported to be mild or moderate, and resolved during the trials.

Dutasteride is not currently approved for use in treatment of male pattern baldness. Future research may indicate whether it may be investigated as a treatment for hair loss.

The 5-alpha-reductase inhibiting drugs are not recommended for use by women who are pregnant or who may become pregnant, or by children.