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Frequently asked questions about Propecia

Originally approved by the FDA to treat benign prostate problems, Propecia had a welcome side effect: hair growth. But the medication also has sexual side effects. Now, a new study says the medication may cause permanent problems. NBC's Dr. Nancy Snyderman reports.

Millions of American men use Propecia to combat baldness and grow hair. The medication, made by Merck, did $134 million dollars in sales last year. But tonight there are new questions about possible long-lasting sexual side-effects. NBC's Dr. Nancy Snyderman answers frequently-asked questions about the latest Propecia study, and the commonly-prescribed drug. 


What is Propecia prescribed for?

Propecia is prescribed for male pattern baldness, a hereditary problem in which men lose hair on the crown and sides of their head.  Propecia is the brand name of a drug called finasteride which is also marketed as Proscar for men with benign enlarged prostate.  This occurs mostly in men over the age of 50 and is characterized by urinary problems.

What did today’s study find?

Today’s study out of George Washington University and published in the Journal of Sexual Medicine was done on younger men mostly in their thirties who were taking Propecia for hair loss.  The study was small, involving only 54 participants, but they found that 96 percent of the men surveyed suffered some kind of sexual dysfunction even after stopping the drug, suggesting permanent damage.  The sexual dysfunction included low libido, problems with arousal and difficulty with erections and orgasms. 

How common are these side effects?

This year the FDA changed the labeling on Propecia to reflect the possibility of sexual side effects.  Still, they’re not very common --clinical trials with the drug suggest sexual dysfunction in only 2 percent of men taking it.  Conventional wisdom has been that most side effects were temporary, but today’s report raises questions as to whether the sexual dysfunction can be permanent.

Should I stop taking the drug?

Don’t stop taking any medication without talking it over with your physician.

How does it work?

Propecia belongs to a class of drugs called 5-alpha reductase inhibitors that blocks the conversion of testosterone to the more potent androgen dihydrotestosterone (dht).  What does that mean? It alters the testosterone effects on the body.  For men with an enlarged prostate it works to shrink the gland.  And as an interesting side effect it causes hair growth.  But this is a drug only intended for men -- there is no medical reason to ever prescribe it to women or children. 

Are there any alternatives for hair loss?

There are topical treatments out there to promote hair growth without serious side effects.  It’s important to weigh the risks and benefits of any cosmetic treatment.  Most men who take a drug for hair growth are doing so for self-esteem and to be more attractive.  But is that benefit worth the risk of possible sexual problems? This is an important decision that should be discussed with your doctor and your partner.