Over a span of 13 years, the agency received 400 complaints of consumers reporting sexual dysfunction. Within those reports, nearly 60 men said that they experienced the side effects for longer than three months after they stopped taking the drug.
In 2011, the FDA ordered a label change for the drug to include a warning about long-lasting erectile dysfunction. They changed the label again in April to add problems with libido, ejaculation, and orgasm disorders.
Merck released a statement claiming that there was not enough evidence proving the relationship between Propecia and prolonged sexual dysfunction.
“Merck believes that Propecia (finasteride) has demonstrated safety and efficacy profiles and that the product labeling appropriately describes the benefits and risks of the drug to help inform prescribing,” the company wrote.
Researchers believe that doctors who are prescribing the drug are simply unaware of the on-going side effects.
“These things just get handed out left and right for any urinary symptoms,” said Dr. Ryan Terlecki, an assistant professor of urology at Wake Forest School of Medicine.
Terlecki has prescribed the drug to patients with large prostates. He believes more research is needed before doctors can entirely pin the side effects on the drug.