Propecia (Finasteride)

Propecia, the brand name for finasteride 1-mg, is the only FDA approved oral medication for hair loss. It now comes in a generic form. Finasteride is particularly helpful in reversing genetic baldness in its early stages and retarding hair loss in older patients.

Male pattern baldness is caused by the effects of the male hormone dihydrotestosterone (DHT) on genetically susceptible hair follicles. DHT is formed by the action of the enzyme 5-alpha reductase on testosterone. It primarily affects hair follicles located on the front, top, and crown of the scalp, not the back and sides. DHT causes hair loss by shortening the growth phase of the hair cycle and miniaturization (a decrease in the size) of the hair follicles. The hair that is affected by DHT becomes shorter and finer until it disappears.

Finasteride should be taken regularly one a day without regard to meals. The full results of Finasteride are not visible for one year or longer of continual use. During the first six months, a person may note some thinning of his existing hair and should not be concerned. This can indicate that the medication is working, as the finer hair is shed to make way for the new, thicker hair.

The side effects from finasteride at the 1-mg dose are uncommon (about 2%) and are reversible. They consist of sexual dysfunction related to a decreased sex drive and an inability to maintain an erection. Other adverse reactions include breast tenderness or enlargement (gynecomastia), which occurred in 0.4% of men taking finasteride 1-mg, but this was no greater than in the control group. Other side effects that were not statistically significant included hypersensitivity reactions including rash, pruritus, hives, swelling of the lips and face, and testicular pain.
Although the Propecia tablets are coated and prevent direct contact of the medication, women who are pregnant or potentially pregnant should not handle crushed or broken tablets as the absorption of finasteride may cause a potential risk to a male fetus. The coating on the Propecia tablet will prevent contact with the active ingredient during normal handling. Exposure of pregnant women to semen from men treated with Propecia poses no risk to the fetus.

Merck, the producer of Propecia carried out a study to evaluate the use of finasteride in post-menopausal women, but found no benefit. It appears that women’s hair loss is related to the enzyme aromatase (which is not affected by finasteride) as well as DHT, possibly explaining the lack of response to DHT blockers. It is also possible that the low DHT levels observed in postmenopausal women are responsible for failure of finasteride to work in this group of patients.

The major benefit of Finasteride is its ability to slow down or even halt hair loss. Finasteride does not grow hair in areas that are completely bald and works best in areas of thinning hair. Although the long-term ability of finasteride to maintain one’s hair is unknown, the majority of men find that after 5 years the medication is still working.

The benefits of finasteride will stop if the medication is discontinued. Within two to six months of stopping the medications the hair loss pattern will return to the state that it would have been if the medication had never been used.

For those who wish to take generic finasteride, one can purchase a pill cutter, available at any pharmacy, and taking ¼ tablet of the generic 5mg tablet per day. However, one should keep in mind that there is no scientific data ensuring that taking ¼ tablet of 5mg finasteride will be as effective as Propecia 1mg per day and there is a potential risk to pregnant women from handling broken or crushed tablets.

Because finasteride depresses PSA levels by about 50%, men aged 50, or over, should inform their general physician or urologist that they plan to take Propecia (finasteride 1mg). In general men over 50 should receive an annual routine evaluation for prostate disease (that includes a rectal examination and PSA). In patients who are African American and/or those who have a family history of prostate disease, annual routine prostate evaluations should begin at the age of 40.

Robert M. Bernstein M.D., F.A.A.D.
Clinical Professor of Dermatology
College of Physicians and Surgeons of Columbia University
New York, New York
Bernstein Medical Center for Hair Restoration
110 East 55th Street, 11th Fl., New York, NY 10022