A number of recent studies have linked the erectile dysfunction drug Viagra to a heightened risk of developing melanoma skin cancer. An increasing number of men are filing lawsuits against the maker of Viagra, Pfizer, claiming that the pharmaceutical manufacturer knew, or should have known, of this risk and failed to warn of it.

Viagra (sildenafil) is in a class of drugs known as phosphodiesterase 5A (PDG5A) inhibitors. This class of drugs also includes Cialis (tadalafil) and Levitra (vardenafil). The medications affect the same genetic pathway that allows skin cancer to be more aggressive and therefore, it may promote melanoma cell invasion.

A study published in the medical journal JAMA Internal Medicine in April 2014 by researchers from Harvard Medical School found that men who use Viagra may be up to 84 percent more likely to be diagnosed with the skin cancer melanoma. Additionally, a study published in the journal Cancer Cell in 2011 linked Viagra to melanoma, as did a subsequent study published in 2012 by the Journal of Cell Biochemistry.

According to the American Cancer Society, melanoma is treatable when diagnosed early. When melanoma is allowed to metastasize to other parts of the body, however, it is very difficult to cure. About 8,650 Americans die of melanoma every year.

Viagra Melanoma Lawsuits

At least three Viagra melanoma lawsuits have been filed in federal courts this past month. On March 13, an Alabama man filed a personal injury lawsuit against Pfizer based on Viagra melanoma claims, and two separate similar Viagra melanoma lawsuits were filed in the U.S. District Court for the Southern District of Mississippi.

These three Viagra skin cancer lawsuits are all based on claims that Pfizer deceived the public by downplaying the risks of Viagra and that they failed to provide warnings of the known risk of Viagra melanoma.

Viagra (sildenafil citrate) was introduced by Pfizer in 1998, and it has become one of the most widely recognized medications in the United States, used by millions of men to treat impotence and sexual dysfunction, including the inability to develop or maintain an erection.

Pfizer reported that Viagra generated $1.8 billion in revenue worldwide in 2013, and the drug has been prescribed to an estimated 35 million men since its 1998 approval.

According to the JAMA study, 3,500 of 26,000 male participants developed skin cancer, which was allegedly caused by their use of Viagra. Of the 3,500 skin cancer patients, 142 specifically developed melanoma.

The Harvard researchers took in other risk factors, including genetics and previous UV damage, into account and found that these additional causes of melanoma did not affect the findings of the study. This may suggest that men taking Viagra are more likely to develop melanoma because of their use of the Pfizer drug.

Men who developed melanoma after using Viagra may be able to file Viagra Melanoma lawsuits against Pfizer, the drug’s manufacturer, seeking compensation for past and future medical bills, lost wages, pain and suffering and other damages.