A Florida man filed a Propecia lawsuit against Merck, alleging that the drug caused him to suffer sexual dysfunction side effects. The Propecia lawsuit was added to multidistrict litigation (MDL) now pending in a New York federal court.

Plaintiff John M. is suing Merck and related companies involved in the manufacture of Propecia, a medication used to treat male pattern baldness. Propecia is also sold under the generic name finasteride.

John says in his Propecial lawsuit that while he was taking the drug he began to suffer sexual dysfunction and cognitive impairment. He says those symptoms continued even after he stopped taking finasteride. He now alleges that these Propecia side effects make finasteride a defective product, and he accuses Merck of failing to properly warn consumers about the risk of Propecia side effects.

Propecia functions by inhibiting the conversion of testosterone to dihydrotestosterone, or DHT. DHT is involved in the development of benign prostatic hypertrophy, and it was originally FDA-approved in 1992 as a treatment for that condition.

However, dihydrotestosterone is also associated with male pattern baldness as a balding scalp contains higher levels of DHT than a hairy scalp. So in 1997, the FDA approved finasteride at a lower dosage and under the brand name Propecia for the treatment of male pattern baldness.

The side effects of Propecia include various types of sexual dysfunction. Erectile dysfunction and loss of sex drive are among the more common side effects.

John’s Propecia lawsuit refers to studies that show sexual dysfunction occurred in finasteride patients at rates as high as 39 percent. John also cites a 2003 report showing that these symptoms did not resolve in half of patients even after discontinuing treatment.

John also reports efforts by regulatory authorities in Sweden and the United Kingdom to address Propecia side effects. In 2008, in response to an investigation by the Swedish Medical Products Agency, Merck added a warning to the label for Propecia sold in Sweden stating that some users had reported persistent erectile dysfunction after discontinuing Propecia treatment. The same reports were mentioned in a December 2009 report by the United Kingdom’s Medicine Health Care Products Regulatory Agency.

According to the FDA’s website, the most recent labeling for Propecia sold in the United States mentions reports of decreased libido, erectile dysfunction, and ejaculation disorder.

John also alleges Merck improperly encouraged doctors to prescribe higher-dosage Propecia for off-label treatment of male pattern baldness. Although doctors have discretion to prescribe drugs for uses not approved by the FDA, it is unlawful for drug manufacturers to promote drugs for any non-approved use.

John’s Propecia lawsuit raises claims for strict liability for defective product design, negligence, breach of warranty, and negligent infliction of emotional distress. He seeks compensation for his injuries, past and future medical expenses, lost income, and pain and suffering, as well as an award for punitive damages based on Merck’s allegedly “wanton, willful, fraudulent, reckless” actions.

He also argues that the statute of limitations should not bar his Propecia lawsuit because Merck’s allegedly knowing and active concealment of vital safety information prevented him from discovering that his symptoms were side effects of Propecia.

The Propecia Lawsuit MDL is In re: Propecia (Finasteride) Products Liability Litigation, MDL no. 2331, pending in the U.S. District Court for the Eastern District of New York