FDA Orders Sexual Side Effect Warnings for Propecia, Proscar


FDA Orders Sexual Side Effect Warnings for Propecia, ProscarOverview: The U.S. Food and Drug Administration (FDA) is ordering updates on the safety labels for Merck’s Propecia and Proscar, which treat male pattern baldness and enlarged prostate, respectively. Apparently, the drugs are associated with sexual dysfunction, which does not necessarily dissipate once the drug is discontinued. The labels will now warn about the risk of libido, orgasm and ejaculation disorders.


  • Proscar and Propecia warnings will now include the risk of sexual dysfunction
  • According to reports received by the FDA, the side effects can persist even after the drug is discontinued
  • Previous studies have also linked Proscar and Propecia to cancer

Product: Propecia (finasteride 1 mg) and Proscar (finasteride 5mg)

Manufacturer: Merck & Co.

Side Effects & Complications

  • Infertility
  • Poor semen quality
  • Libido, orgasm and ejaculation disorders
  • Male breast cancer
  • Prostate cancer                           

Reports Prompt FDA to Update Labels

The FDA’s decision was fueled by 421 reports of sexual dysfunction in Propecia users from 1998 to 2011; 59 of these cases persisted three months after the drug was stopped.  The agency also reviewed data for Proscar from 1992 to 2010, documenting 131 cases of erectile dysfunction and 68 cases of decreased libido. While Propecia’s label will be modified to include libido, orgasm and ejaculation disorders, Proscar’s warning will only mention decreased libido.

While the reports are unsettling, the FDA is cautious about directly attributing the sexual side effects to the drugs. “Despite the fact that clear causal links between finasteride (Propecia and Proscar) and sexual adverse events have not been established, the cases suggest a broader range of adverse effects than previously reported in patients taking these drugs,” the agency stated.


Propecia and Proscar both have finasteride as their active ingredient, but in different doses; Propecia comes in 1 mg doses while Proscar contains 5 mg per dose. Some studies have linked the use of finasteride to an increased risk of cancer.

Last March, the Journal of Sexual Medicine published a study of 70 men who had taken Propecia. In these patients, researchers found that sexual side effects continued to persist for an average of 40 months after men stopped taking the drug.

Last June, the FDA warned that Propecia and Proscar may increase the risk of high-grade prostate cancer, which is more aggressive than other forms of cancer.