The Food and Drug Administration on Thursday expanded the warning label on the drug finasteride, which is used to treat enlarged prostate and male pattern baldness, saying some men who took the drug continued to have sexual side effects after they stopped taking it.
Finasteride is the main ingredient in Merck & Co.'s prostate drug Proscar and its baldness treatment Propecia, and in generic equivalents. The drug has been linked to other sexual side effects, but the FDA said it was making further changes to the warning label because some side effects have been noted to continue after patients were no longer taking the drug.
The revised warning label for Propecia says some men who took the drug experienced libido disorders, ejaculation disorders, and orgasm disorders that persisted after they were no longer taking it. The label for Proscar now includes decreased libido, and the labels for both drugs were amended to include a description of reported cases of male infertility and poor semen quality that got better or normalized after patients stopped taking the drug.
Proscar was approved in 1992 for symptoms of enlarged prostate, and it is used to reduce the risk of urinary retention or need for surgery in those patients. Propecia was approved in 1997 for treatment of male pattern hair loss.
Finasteride has been shown to reduce the risk of prostate cancer, but in June 2011, the FDA updated the drug's warning label to say that finasteride may increase the risk of a more serious type of prostate cancer.