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.