Federal lawsuits over the alleged link between Viagra and melanoma will be consolidated in a San Francisco court, according to an order by the Judicial Panel on Multidistrict Litigation (JPML).

In April 2016, fourteen claims against Viagra’s manufacturer Pfizer were set to be overseen by District Judge Richard Seeborg as part of a single multidistrict litigation, or MDL.

Plaintiffs in the Viagra lawsuits requested the transfer, and Pfizer, Viagra’s manufacturer and the defendant, did not oppose the request.

Future federal lawsuits filed over the same allegations of the effects of Viagra will likely be transferred into this MDL, regardless of where they are filed.

Given the widespread use of Viagra, hundreds and possibly thousands of such lawsuits could eventually be filed.

Generally, plaintiffs in these lawsuits allege that Viagra caused them to develop skin cancer. They say that Pfizer knew or should have known about the link between Viagra and melanoma as early as 1998, when the drug was first approved by the FDA.

They fault Pfizer for failing to warn them that the side effects of Viagra could include a greater likelihood of developing melanoma, one of the more aggressive forms of skin cancer.

The Viagra MDL is pending under MDL No. 2691, In re: Viagra (Sildenafil Citrate) Products Liability Litigation.

Research on Viagra and Skin Cancer

In its nearly two decades on the market, Viagra has been extraordinarily popular. It was prescribed eight million times in 2012. Sales worldwide have exceeded $18 billion. Thanks in part to Viagra’s popularity, Pfizer now holds about 45 percent of the market for erectile dysfunction drugs.

Yet at the same time, recent research has suggested a possible link between Viagra and development of skin cancer.

In one study published in JAMA Internal Medicine in June 2014, researchers examined the histories of over 25,000 men from 2000 to 2010 who had no cancer to report initially.

They found that men who had used Viagra, referenced in the study by its generic name sildenafil, had a significantly greater chance of developing melanoma than men who had not used it.

They researchers noted no similar increase in incidence of other types of skin cancer, specifically squamous cell carcinoma and basal cell carcinoma.

While they also noted the study was not an adequate basis for altering clinical recommendations, they recommended continued investigation of the association between Viagra and melanoma.

More recently, a new study found that one of the effects of Viagra may be to promote the growth of skin tumors.

In this study published in the journal Cell Reports in March 2016, researchers theorize that sildenafil promotes the activity of a “signaling molecule” called cGMP, part of a signaling pathway that causes malignant melanoma cells to grow.

The researchers say that sildenafil appears to inhibit the activity of an enzyme called PDE5, which itself inhibits the activity of cGMP. So with less active PDE5 around, cGMP is more effective in the growth process of melanoma, the researchers say.

They believe this mechanism could explain the increased risk of melanoma in sildenafil patients.

Melanoma is the deadliest known form of skin cancer. If caught early and treated, almost all cases can be resolved. But if left untreated, melanoma may metastasize and spread to other parts of the body, dramatically worsening the patient’s prognosis.

If you or someone you love was diagnosed with melanoma while using Viagra or other erectile dysfunction drugs, you may have legal resource. Personal injury lawyers are available to help victims and their families pursue compensation.