For Some Men, Propecia's Sexual Side Effects May Be Long-lasting

July 12, 2012— -- Kevin Malley was almost 30, and he was starting to lose his hair. He went to his doctor to see if there was a way to keep from going bald, and his doctor prescribed Propecia.

"I looked young for my age, so I wanted to hold off my hair loss for a little bit," Malley said. "I didn't plan on taking Propecia for more than a year."

Malley started taking the drug in May 2011, and by October he was completely impotent and had no sex drive whatsoever. His body changed, even his genitals shrank, and he slipped into a mental fog that he just couldn't clear. His doctor told him the side effects would go away if he stopped taking the drug, so he did. But nothing changed.

"I kept expecting the side effects to go away, but they did not, they only got worse," he said.

Malley is not alone: A new study published today in the Journal of Sexual Medicine suggests that for some men, the sexual side effects of Propecia may last for months to years, even after they stop taking the drug.

Researchers from George Washington University interviewed 54 men under age 40 who reported side effects for three months or more after taking Propecia, also called finasteride, to treat their hair loss. None of the men reported having any sexual, medical or psychiatric problems before they took the drug. Some of the men took the drug for a few weeks, others took it for years, but all of them reported side effects such as erectile dysfunction, decreased sexual drive, problems with orgasms, shrinking and painful genitals, even some neurological problems, such as depression, anxiety and mental fogginess.

For 96 percent of the men, the sexual problems lasted for more than a year after they stopped taking the drug.

"Our findings make me suspicious that this drug may have done permanent damage to these men," said Dr. Michael Irwig, the author of the study. "The chances that they will improve? I think it's lower and lower the longer they have these side effects."

Irwig cautions that it's possible that only men who were the most affected by the drug participated in the study. Because he recruited his study participants through an online forum called PropeciaHelp, a group for men who have experienced persistent sexual side effects from the drug, he said the study may not have included men who have fewer or less pervasive side effects.

FDA, Merck Know of Drug's Side Effects

Finasteride works by blocking the conversion of testosterone into a more potent form, called DHT, which contributes to hair loss. It was originally developed in 1992 by drug giant Merck as a treatment for enlarged prostates and sold as the drug Proscar.