(WASHINGTON) -- The baldness drug finasteride has left some young, otherwise healthy men with persistent impotence, diminished sex drive and depression long after they've stopped taking it, according to emerging medical studies and patient reports, as well as lawsuits filed in the United States and Canada.
Millions of men have taken five-mg finasteride tablets since the U.S. Food and Drug Administration in 1992 approved Merck and Co. Inc's Proscar for non-cancerous enlargement of the prostate gland. Millions more have taken finasteride since FDA's 1997 approval of Propecia, Merck's lower-dose (one mg) formulation for male-pattern baldness, which affects about half of all men.
In 2002, the FDA approved GlaxoSmithKline's closely related drug dutasteride (Avodart) to shrink enlarged prostates, further expanding the market for name-brand and generic 5-alpha reductase inhibitors. The drugs block an enzyme that converts the male sex hormone testosterone to dihydrotestosterone, which is toxic to hair follicles, but important for healthy sexual functioning.
Although the generally rare sexual side effects of finasteride and dutasteride have been mentioned at urology meetings, information about potentially irreversible consequences hasn't yet reached the larger community of prescribing physicians, such as dermatologists and primary care doctors -- or their patients, said researcher Abdulmaged M. Traish, a professor of biochemistry and urology at Boston University School of Medicine.
For an article published in the March issue of the Journal of Sexual Medicine, Traish and a BU colleague, along with endocrinologists from Peabody, Mass.; Germany and Norway, reviewed available scientific studies on the adverse effects of finasteride and dutasteride. Although the overall percentage of men reporting sexual side effects was small, ranging from 5 percent to 23 percent, Traish said half of them never had their side effects go away.
"We found out that we're really ignoring the important part, especially those in whom the problem becomes persistent," Traish said in an interview Wednesday. "That's the group that everybody forgot. We have to worry about the consequences for people who are going to suffer -- even after they discontinue the drug -- from continuous loss of libido and potential depression." Other observed effects included reduced ejaculation and smaller volume of semen.
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