'Viagra could increase risk of cancer' - Study finds

Researchers have said that men who use Viagra and similar drugs for erectile dysfunction could be at greater risk of developing skin cancer.

A study of more than 4,000 men in Sweden found that those who were prescribed a single course of the drugs were one third more likely to develop a malignant melanoma.

Also men who had multiple prescriptions the risk was raised by 20%.

While the risk was still small, a one in 25 chance of developing cancer compared with the usual one in 33 risk, researchers from New York University said the findings were still statistically significant.

Drugs like Viagra and Cialis work by turning off the enzyme PDE5, a chemical which takes away an erection after sex by limiting blood supply.

But Dr Stacy Loeb of New York University said "the use of PDE5 inhibitors was associated with a modest but significant increased risk of malignant melanoma"

Viagra was formulated by pharmaceutical company Pfizer and was launched as a sex-enhancing medication in Britain in 1999, although it was originally developed to treat high blood pressure and angina but was found to be ineffective for these conditions.

Health experts in the UK, however said men should not be overly concerned by the findings and said it could be driven by other factors such as income and exposure to sunlight.

Said Prof Stephen Evans, Professor of Pharmacoepidemiology, at the London School of Hygiene and Tropical Medicine

“This study is extremely weak evidence for an increase in risk of malignant melanoma with ED drugs, and seems much more likely to be associated with other factors, especially exposure to sunlight.”