In 1992, the Food and Drug Administration (FDA) approved the use of Proscar (finasteride, 5 mg) to treat benign prostate enlargement. Five years later, in 1997, the FDA gave the go-ahead to use the finasteride in one-milligram doses to treat male pattern baldness. Merck, the drug's manufacturer, marketed the new wonder drug as Propecia – the first hair-loss remedy available in pill form.
When Propecia first hit the market, Merck warned of several side effects that included a low risk of Propecia erectile dysfunction. However, later studies revealed that the risk of sexual side effects were higher than originally estimated.
Sexual Side Effects
During the initial FDA-approval process, Merck's clinical studies reported that use of Propecia showed a less than two percent chance of Propecia sexual side effects such as decreased libido, erectile dysfunction (ED), and a decreased amount of ejaculate. Additionally, a small percent of men experienced testicular pain and breast enlargement. The original label for Propecia warned users against these side effects.
More Serious Side Effects Reported
In 2008, nine years after Propecia hit the market, the Swedish Medical Products Agency revealed that finasteride products could result in permanent sexual side effects. After the United Kingdom's Medical and Healthcare Products Regulatory Agency (MHRA) reported similar findings of persistent erectile dysfunction, Europe updated its product labels to say that Propecia could cause permanent sexual side effects. In 2009 the United Kingdom also added a warning regarding male breast cancer to the drug's label. In the United States, male breast cancer is also included on Propecia's warning label.
Depression and High-grade Prostate Cancer Added as Side Effects
After several reports of depression following use of Propecia, in 2010 the FDA added this to the product's warning label.
On June 9, 2011, the FDA also required that high-grade prostate cancer be added to the warning labels for all finasteride products. The synthetic antiandrogen is generally considered to reduce the risk of low-grade prostate cancer, but only recent studies revealed that it could increase the risk of high-grade prostate cancer.
Additional Studies
In 2011, two separate studies found that sexual side effects resulting from the use of Propecia could persist after patients had ceased taking the medication. Continuing effects, which lasted 40 months on average, included erectile dysfunction and decreased libido.
As a result, in June 2011 the FDA ordered Merck to add persistent erectile dysfunction to Propecia's warning label. This marked the first time that Propecia product labels in the U.S. included warnings of long-term effects.
Propecia Lawsuits
In response to new study results and the additional, persistent and serious side effects of Propecia, New Jersey courts welcomed the first lawsuits against Merck and Propecia. It is likely that many more lawsuits will be filed due to Merck's failure to disclose information regarding Propecia's long-term side effects.
