Finasteride

About Finasteride

Finasteride is a drug used to treat benign prostatic hyperplasia (enlarged prostate) and hair loss. 

Medical uses

Doctors use finasteride to treat DPH, informally known as prostate enlargement. Finasteride can improve symptoms associated with prostate adenoma, such as difficulty urinating, getting up at night to urinate, hesitation in starting to urinate, and decreased urine flow. It provides less symptomatic treatment than alpha-1 blockers such as tamsulosin and symptom relief is slower in the beginning (it may take six months or more for treatment with finasteride to determine the therapeutic results of treatment).

Finasteride is used to treat hair loss (androgenic alopecia) only in men. The treatment slows further hair loss and provides about 30% improvement in hair loss after six months of treatment, with effectiveness lasting only as long as the drug takes it. Finasteride has also been tested for hair loss in women; but the results were no better than placebo.

Contraindications

Finasteride is not intended for use in women, especially because of the risk of birth defects in the fetus. It is classified by the FDA in pregnancy category X

Side effects

Side effects from finasteride are rare. Compared to placebo, men taking finasteride are at increased risk of impotence, erectile dysfunction, decreased libido, and impaired ejaculation during the first year of treatment. The rate of these effects becomes indistinguishable from placebo after 2 to 4 years, and these side effects usually subside over time. The FDA added a warning about 5-alpha reductase regarding the increased risk of high-grade prostate cancer, because treatment of BPH reduces PSA (prostate-specific antigen) levels, which could mask the development of prostate cancer. Although the overall incidence of breast cancer in men in clinical trials for finasteride was not increased by 5 mg, there is a post-marketing report of breast cancer due to its use. The available data are unclear as to whether there is a causal relationship between finasteride and these cancers.

A 2015 meta-analysis found that none of the clinical trials testing finasteride in hair loss adequately reported, on safety and there is insufficient information to establish a safety profile for finasteride as a treatment for hair loss. The study concludes that existing clinical trials of finasteride for hair loss provide very limited information on toxicity, poor quality, and systematic bias toward identifying side effects. In addition, trials submitted to the FDA have excluded most men in the hair loss claims that would normally prescribe finasteride for androgenic alopecia.