About Finasteride

Finasteride is a 5-alpha-reductase inhibitor in both tissue and liver enzymes. The enzyme 5-alpha-reductase converts testosterone to dihydrotestosterone (DHT). Finasteride therefore decreases the serum levels of DHT. DHT is responsible for male pattern baldness and prostate growth in addition to other roles in the body.

Pharmacodynamics

After one dose of 0.5 mg of finasteride, there is a 65 percent depression of plasma DHT levels that lasts for five to seven days. With six months of 5 mg per day treatment, the levels of DHT reach castrate levels. There are no effects on circulating testosterone. Discontinuing the medication causes levels to return to normal in approximately 14 days.

Side Effects

The major side effects of finasteride include impotence and decreased libido. Hypersensitivity reactions including rash and hives and facial swelling can also occur. It is advised that women, particularly pregnant women, not handle the drug due to specific birth defects. It is pregnancy risk factor X, therefore it has a known negative impact on a fetus. Also, the excretion into breast milk is unknown, therefore it is contraindicated.

Benign Prostatic Hyperplasia

Treatment for benign prostatic hyperplasia (BPH) with finasteride consists of 5 mg per day.The brand name is Proscar. Long-term treatment is required to maintain the effects of shrinking the prostate. The treatment can be combined with alpha-blockers such as doxazosin.

Male-Pattern Baldness

The brand name Propecia is the formulation of finasteride for use in the treatment of male-pattern baldness. Propecia comes as a 1 mg per day tablet. This indication is for men only. Duskova found in 2010 that men treated with 1 mg per day of finasteride for male-pattern baldness had positive effects on their metabolic profiles and even a slight improvement in glucose.

Prostate Cancer Prevention

Prophylaxis for prostate cancer with finasteride is an off-label use. The treatment dose is 5 mg a day for seven years. Dr. Patrick Walsh in the "New England Journal of Medicine" states that men who take finasteride may have a false sense of security when in fact the medication does not reduce the risk of prostate cancer and may in fact just shrink a tumor and lower the prostate specific antigen, or PSA, making detection more difficult.

Female Hirsutism

The treatment for female hirsutism (a condition of unwanted, male-pattern hair growth in women) with finasteride is an off-label use. The dose is 5 mg a day orally.