The risks of taking Viagra may outweigh the benefits for some men who rely on “the little blue pill” to put a skip in their step. The FDA approved Viagra for use in erectile dysfunction in March 1998, but it’s only been since 2014 that researchers have believed there’s a possible connection between Viagra and an increased risk of skin cancer.

Who Determined the Risks of Taking Viagra May Include an Increased Risk of Skin Cancer?

According to the April 2014 issue of JAMA Internal Medicine, more than 3,500 diagnoses of skin cancer allegedly linked to Viagra were reported among 26,000 men from 2000 to 2010. Basal cell carcinoma, squamous cell carcinoma, and melanoma were all found. The study, conducted by the Warren Alpert Medical School at Brown University, took into account a man’s family history, sunlight exposure, mole count and other factors. Ultimately, according to NBC News, the researchers said men who had taken Viagra were 84 percent more likely to develop melanoma than men who never took the drug.

Several other studies, including one involving 15,000 men in the U.S. and another involving 24,000 men in Sweden have also pointed to a link between Viagra and melanoma and other skin cancers.

Does Viagra Help Skin Cancer Cells Develop?

Viagra belongs to a class of medications called phosphodiesterase (PDE) inhibitors. The medications work by increasing blood flow to the genital area.

Cells contain an enzyme called PDE5, which signals certain molecules called cGMP molecules to open and close metabolic pathways.

According to MedicalNewsToday.com, Prof. Robert Feil from the University of Tubingen in Germany published a study in a 2016 issue of Cell Reports medical journal, saying in part that he and fellow researchers “have discovered that the cells of malignant melanoma also use the cGMP signaling pathway for their growth.”

Because Viagra is in the class of drugs known as PDE inhibitors and because the PDE5 enzyme in particular appeared to be inhibited by Viagra in experiments, Feil said Viagra allegedly could provide melanoma with an easy path, allowing the cancer to grow more quickly.

However, some researchers have suggested that the link may also be due in part to lifestyle choices made by men who take Viagra, including sun bathing, using tanning beds, and other activities that increase the risk of skin cancer.

What is Malignant Melanoma?

Malignant melanoma is the most deadly type of skin cancer and begins in the melanin, which is responsible for the skin’s pigmentation. According to MayoClinic.org, melanoma appears most often in areas that have abundant sun exposure, such as the back, legs, arms and face. Some 50,000 cases of melanoma are diagnosed in the U.S. every year.

Melanoma is usually first detected by a change in the size, shape or color of an existing mole or the development of a new pigmented area or growth on the skin. Although melanomas are generally not painful, they may result in skin scaling, burning, or itching, or lesions that change in texture, form a scab, or become inflamed. Unfortunately, many melanomas do not result in any noticeable symptoms, making it difficult to diagnose these cases before they are at an advanced stage. When caught early, melanoma can be successfully treated. When melanoma is diagnosed before it spreads, the five-year survival rate is about 99 percent. However, this percentage may drop to as low as 25 percent once the disease spreads to the lymph nodes or other organs.

What Are Other Risks of Taking Viagra?

According to the product’s website, Viagra may cause sudden vision loss in one or both eyes, which can be an indication of a serious condition called non-arteritic anterior ischemic optic neuropathy (NAION).

Sudden hearing loss is possible as well, which may be accompanied by ringing in the ears or dizziness.

Pfizer says the most common side effects include headache, upset stomach, blurred vision or visual changes in color, such as a feeling of looking through a blue lens. Other men may suffer a stuffy or runny nose, back pain, muscle pain or a rash.

The site also warns patients who take nitrates for chest pain or certain blood pressure medications not to take Viagra because blood pressure could drop too low.

Potentially due to concerns regarding the risks of taking Viagra, U.S. sales of Viagra decreased by more than 70 percent from 2017 to 2018, dropping from nearly $780 million to $217 million, according to Newswire.

Additionally, at least 1,000 lawsuits have been filed against Viagra’s manufacturer by plaintiffs who claim to have developed skin cancer and other health conditions after taking the drug.