Merck & Co. (MRK)’s baldness drug Propecia and enlarged prostate therapy Proscar will carry labels linking them to sexual dysfunction after the treatments are no longer used, U.S. regulators said.
Propecia’s packaging will include warnings about libido, orgasm and ejaculation disorders that occur after patients stop using the medicines, the Food and Drug Administration said yesterday in a statement. Proscar’s similar warning is limited to decreased libido, and both drugs will include on their labels reports of infertility and poor semen quality that normalized when people stopped using the drugs, the agency said.
“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 FDA said in its statement.
The FDA reviewed 421 reports of sexual dysfunction from 1998 to 2011 related to Propecia. Of these, 59 cases reported the condition lasted longer than three months after drug discontinuation. The agency reviewed 131 cases of erectile dysfunction and 68 cases of decreased libido with Proscar from 1992 to 2010.
“Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure,” Pamela Eisele, a spokeswoman for Merck, said in a statement. “Merck believes that Propecia and Proscar are generally well tolerated and effective for their respective indicated use when used in accordance with their approved labeling.”
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