Pfizer may face a wave of Viagra lawsuits after a study showed the possibility the popular erectile dysfunction drug could increase the chances users could develop melanoma. Because the drug’s warning label does not mention this side effect, Viagra lawsuits allege negligence, false advertising, concealing information, and misrepresenting a product.

According to a study published in this month’s issue of the medical journal JAMA Internal Medicine, Harvard Medical School researchers indicate that men who take Viagra may face up to an 84 percent increased risk of developing melanoma, a type of skin cancer. This study analyzed approximately 26,000 men over a 10-year period.

During the decade, more than 3,500 cases of Viagra skin cancer were reported, with 142 cases being melanoma. More than 3,000 were basal cell carcinoma. The researchers suggested that the active ingredient in the drug, sildenafil citrate, may decrease the propensity of a cancer-fighting protein called PDE5A, which allows for an increased possibility of melanoma cancer cells to invade. No additional risk was found with other forms of skin cancers.

Since the study has been released, several law firms have announced they are in the process of reviewing potential Viagra-induced melanoma cases on the behalf of former Viagra users. Men who have already filed Viagra melanoma lawsuits have said that they never would have taken the drug if they had known melanoma was a side effect.

Overview of Viagra Melanoma Complications

Viagra has been on the market since its approval by the U.S. Food and Drug Administration (FDA) in 1998 to treat erectile dysfunction. In 2012, Viagra had garnered $2 billion in sales for Pfizer. The findings of this study have raised the question of the drug’s safety, and suggest that Pfizer may have failed to take the proper precautions to protect its customers against the drug’s side effects. Critics also question whether the drug is safe enough to keep on the market.

The American Cancer Society notes that melanoma is diagnosed in approximately 69,000 Americans each year, and is the cause of 8,650 deaths annually. The skin cancer usually shows its first signs with unusual moles or patches of skin that appear suddenly. While the cancer can be curable if caught early enough, melanoma can potentially spread beyond the skin and into the patient’s body if left untreated.