Propecia (Finasteride) is a popular drug used as a treatment for male pattern baldness. Initial research and other studies show that the drug is very effective in controlling the hair fall, inducing hair regeneration and improving the hair density. Finasteride is not a new drug, it has been used for years for the treatment of benign prostatic hypertrophy, a condition that occurs in older males. Finasteride acts by blocking the conversion of testosterone into a powerful sexual hormone dihydrotestosterone. Research into the hair fall had revealed dihydrotestosterone to be the culprit for excess hair fall in males. Propecia by blocking the production of dihydrotestosterone prevents hair fall. But dihydrotestosterone being a powerful sexual hormone plays a significant role in various sexual functions. It enhances male libido, sexual interest, plays a role in the initiation and maintainence of erection, induces the glands to secrete the components of what we call as semen. Basic physiological considerations would reveal that the absense of dihydrotestosterone would result in decreased sexual interest, decreased volume of semen and erectile dysfunction.
Merck and Co, the giant pharma company that markets propecia agrees that adverse sexual side effects does indeed occur but claims that these occur only in 2% of males taking propecia. They also claim the the sexual side effects disappear once the drug is stopped. But claims from several users reveal that propecia can cause irreversible sexual dysfunction including infertility. In a case report published in BBC, a 26 year old male after taking propecia developed impotence. Impotence didnt resolve after the drug was stopped. The patient then underwent testosterone therapy for impotence, which was unsuccessful. The doctor finally offered the option of having a penile implant.
Now there wont be many virile men who would be willing to risk their sexual health and have a penile implant just for the sake of few strands of extra hair. There might be a possibility that the pharma company is underreporting the sexual side effects of propecia. Even if the sexual side effects are reversible by stopping the drug, in some anxiety prone individuals even a temporary impotence may change their sexual image and lead to life long fear of impotence. This 'fear of impotence' can itself cause impotence in the next sexual encounter and this leads to a vicious cycle. While initially the impotence was caused by the medication, now the impotence continues due to unresolved fear of impotence and anxiety.
Another issue that has not been adequately addressed is sexual relation with women who are planning for pregnancy or currently pregnant. Merck and Co advises pregnant females to not even touch the drug with hand, as the drug can interfere with the genital development of the fetus. Assuming a situation that the husband is taking propecia, and a little concentration of this drug is present in the semen, then the wife would be exposed to propecia and this can lead to congential genital malformations in the baby. This implies that any male with a partner who is planning for pregnancy or pregnant should not take this drug.
Individuals with male pattern baldnes need to seriously consider the potential side effects of propecia/finasteride and discuss with your dermatologist/sexologist prior to the initiation of this drug.
Decreased fertility in male rats administered the 5 alpha-reductase inhibitor, finasteride, is due to deficits in copulatory plug formation. Reprod Toxicol. 1991;5:353–362
Finasteride-associated male infertility. Rev Hosp Clin Fac Med Sao Paulo. 2004;59:203–205