Note: Women who are pregnant or may become pregnant should not use finasteride or handle the crushed or broken tablets. Finasteride can cause birth defects in male babies.
Finasteride is used to treat men with benign prostatic hyperplasia (BPH) and male pattern hair loss, also called androgenetic alopecia. BPH is caused by an enlarged prostate. Men with BPH usually have difficulty urinating, a decreased flow of urination, hesitation at the beginning of urination, and a need to get up at night to urinate. Finasteride will make these symptoms less severe and reduce the chance that prostate surgery will be needed. It may be used alone or in combination with other medicines such as an alpha-blocker (doxazosin, Cardura®) to treat BPH. For men with hair loss, finasteride will increase the number of scalp hairs but will not increase the amount of body hair.
Finasteride blocks the action of an enzyme called 5-alpha-reductase. This enzyme changes testosterone to another hormone that causes the prostate to grow or hair loss in males. It will increase testosterone levels in the body, which decreases prostate size and increases hair growth on the scalp. The effect of finasteride on the prostate and scalp will only last as long as the medicine is taken. When it is stopped, the prostate begins to grow again and the hair will be lost.