Propecia, Other 5-ARIs Pose Risk of Erectile DysfunctionAug 22, 2011 | Parker Waichman LLP
Propecia and other drugs known as 5-alpha reductase inhibitors (5-ARIs) have been linked to erectile dysfunction, and other sexual problems in men. Now research is showing that erectile dysfunction associated with Propecia and similar drugs can sometimes be irreversible.
Propecia (finasteride 1 mg) is used to treat male pattern baldness. Other 5-ARIs such as Proscar (finasteride 5 mg), Avodart (dutasteride) and Jalyn (dutasteride and tamsulosin) are used to treat an enlarged prostate.
Propecia and these other drugs work by preventing the conversion of androgen testosterone to DHT, a hormone critical to male sexual performance. Merck's label for Propecia warns that side effects may include sexual dysfunction but says the side effects “resolve after discontinued use of the drug.”
In April, nine men filed suit against Merck claiming Propecia caused them to develop persistent erectile dysfunction. The lawsuit, which was filed in federal court in New Jersey, points out that in 2006, Swedish drug regulators began investigating reports of persistent sexual dysfunction in men who had stopped taking the drug. While Merck modified the label for Propecia in Sweden, Italy and the United Kingdom to reflect this side effect, the U.S. label - revised in 2010 - did not include an "updated warning regarding the persistence of sexual dysfunction," the lawsuit claims.
The lawsuit further claims that the U.S. Food & Drug Administration (FDA) has received a multitude of complaints about sexual dysfunction from Propecia, and that many doctors, in the United States and Europe, have "publicly expressed concerns about patients who have permanent sexual, mental and physical side effects after discontinuing finasteride."
A month before the men filed their Propecia lawsuit, a group of researchers at Boston University published a study finding that in a small number of cases, erectile dysfunction linked to 5-ARIs may continue after the drugs have been discontinued. The study, which involved a review of available medical literature, found that 8 percent of men taking 5-ARIs reported erectile dysfunction and 4.2 percent reported reduced libido. In the placebo group, only 4 percent reported erectile dysfunction, while only 1.8 percent reported reduced libido. Other men taking the drugs reported reduced ejaculation and semen volume and depression. In some cases, men experienced problems after taking the drugs.
"Extreme caution should be exercised prior to prescribing 5-ARIs therapy to patients for hair growth or for BPH (enlarged prostate) symptoms," the authors write. "In some patients, these adverse effects are persistent and may be prolonged and patients do not recover well after discontinuation from drug use."