A new study found that men taking Propecia for baldness may experience sexual side effects that can last from four months to a year.
Researchers at George Washington University interviewed 54 men under the age of 40 who reported having side effects for three months or longer after taking Propecia (also known as finasteride) to treat their hair loss. None of the men reported having sexual, medical, or psychiatric problems prior to taking the medicine.
The amount of time the men took the medicine varied among the participants. The men reported experiencing side effects such as erectile dysfunction, decreased sexual drive, problems with orgasms, shrinking and painful genitals, and some neurological problems like anxiety and depression.
Ninety-six percent of the men said that the side effects lasted longer than a year after they stopped taking the medicine.
“Our findings make me suspicious that this drug may have done permanent damage to these men,” said Dr. Michael Irwig, the study’s author. “The chances that they will improve? I think it’s lower and lower the longer they have these side effects.”
Study participants were recruited through an online forum called PropeciaHelp, a place where men communicated about their side effects from the drug. Dr. Irwig believes since the participants were solely taken from the forum, the results do not include responses from men who experienced fewer and less pervasive side effects.
Propecia works by blocking the conversion of testosterone into a more powerful form known as DHT, which causes hair loss. Finasteride was originally developed in 1992 by Merck who used the drug to treat enlarged prostates. It was also initially marketed under the name Proscar.
In 1997, The U.S. Food and Drug Administration approved Propecia and Merck recognized reports from men experiencing side effects during the drug’s clinical trials. The company said that the side effects were treated once the men stopped taking the drug.
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.