Viagra Use Could Increase Melanoma Risk by 20 Percent
A new research study shows that men who use Viagra and similar drugs to treat erectile dysfunction could be at greater risk of developing skin cancer.
The study, published this week in the Journal of the American Medical Association, looked at more than 4,000 men in Sweden and found that those who were prescribed a single course of an erectile dysfunction drug were one third more likely to develop a malignant melanoma. For men who had multiple prescriptions, the risk was raised by 20 percent, the (U.K.) Telegraph reports.
Though the risk is still small—going from the usual one in 33 risk of developing melanoma to a one in 25 chance—New York University researchers said the findings were still statistically significant. “The use of PDE5 inhibitors was associated with a modest but significant increased risk of malignant melanoma,” said Dr Stacy Loeb of New York University, one of the study’s authors.
Drugs like Viagra (sildenafil) and Cialis (tadalafil) help men achieve an erection y turning off the enzyme PDE5, a chemical that takes away an erection by limiting blood supply to the penis. But scientists think PDE5 plays an important role in preventing the spread of skin cancer. A faulty gene (BRAF) suppresses the enzyme and this fuels malignant melanoma. Viagra and drugs like it could be mimicking the effect of the mutated BRAF gene, the Telegraph explains.
The drug maker Pfizer originally developed Viagra to treat high blood pressure and angina but the drug was ineffective for these conditions. But male patients noticed that the drug led to sustained erections—the result of temporarily increased blood flow to the penis—and the company then secured approval to market the drug to treat erectile dysfunction.
Prof. Stephen Evans, Professor of Pharmacoepidemiology, at the London School of Hygiene and Tropical Medicine, said the risk of malignant melanoma associated with erectile dysfunction drugs may also be associated with factors like wealth and exposure to sunlight. “It may be the wealthy . . . are able to travel to the sun in Sweden’s winter! It may be that those who travel are also more likely to use ED drugs.” Prof. Chris Chapple, a urological surgeon, who is secretary general of the European Association of Urology, and an honorary professor at Sheffield Hallam University, said there is “a lack of an association between dosing and incidence.” Chapple said at this time he would not recommend “any change in current clinical practice relating to the use of for the treatment of erectile dysfunction,” according to the Telegraph. A spokesman for Pfizer said the company is “committed to ensuring patient safety” and evaluates “any adverse events reported to Pfizer directly or indirectly through secondary sources.”
