A recent quarterly earnings statement by Pfizer has indicated flagging sales for Viagra. While Pfizer’s report cites the fact that the drug’s patent recently expired, Viagra melanoma could lead to Viagra lawsuits.

According the quarterly statement, Pfizer’s patent for the “Little Blue Pill” expired, allowing competing drug makers to legally manufacture and sell generic versions of the drug. Since Viagra now has to compete with generic pills, Pfizer loses money as it has to lower Viagra’s price to compete and as a substantial portion of their market goes to competitors.

This has resulted in a 3 percent decline in the U.S. market and a whopping 22 percent decline worldwide, translating into a major decrease in revenue for Pfizer.

However, off-brand Viagra isn’t the only potential problem for Pfizer. New studies have suggested that Viagra side effects could include melanoma, the most deadly form of skin cancer. A study published in the April issue of JAMA Internal Medicine found that men taking Viagra were 85 percent more likely to be diagnosed with melanoma skin cancer than those not taking the drug.

The Harvard Medical School-based researchers set up a cohort study with data from more than 25,800 men. The researchers found that Viagra was only associated with an increased risk of one type of skin cancer — melanoma.

Researchers prepared a proposed mechanism, suggesting that Viagra could interfere with the production of cancer-fighting compounds in the body. Additionally, researchers did not find an increased risk of melanoma in men with erectile dysfunction who did not take Viagra.

Melanoma is less common than other types of skin cancer. However, it is the most deadly. While more than 90 percent of cases can be cured if it is caught before it spreads, Melanoma still accounts for more than three-quarters of deaths from skin cancer.

If melanoma spreads beyond the skin, it can find its way into other tissues like the lungs, brain, and the lymphatic system, causing widespread damage in the body.

The alleged risk of Viagra melanoma could lead to Viagra melanoma lawsuits. Such a Viagra lawsuit could allege that the makers of Viagra were aware — or reasonably should have been aware — of the risk of melanoma associated with its drug.

Indeed, under federal law, the makers of a drug have a legal duty to thoroughly test drugs for safety and efficacy. And this responsibility does not end once the drug is approved by the U.S. Food and Drug Administration (FDA).

Pharmaceutical companies are required to monitor postmarket reports of complications to look for side effects not seen in the initial clinical trials. Such a Viagra lawsuit could allege that Pfizer was aware of the risk of Viagra melanoma and did not do enough to protect the public, despite reaping billions in profits from the drug.