In the journals
The erectile dysfunction drugs collectively known as phosphodiesterase type 5 (PDE5) inhibitors, such as sildenafil (Viagra), may not cause melanoma, the most dangerous form of skin cancer, according to a study published online May 19, 2017, by the Journal of the National Cancer Institute.
In 2016, the FDA put PDE5 inhibitors on its watch list of medications with possible safety issues after some studies suggested they might increase the risk for melanoma. In response to the FDA's action, researchers analyzed data from five large-scale studies of the issue, involving 866,049 men, published between 2014 and 2016.
The researchers found an overall 12% higher risk of developing melanoma among men who used PDE5 inhibitors. However, PDE5 inhibitors were only associated with stage zero melanoma, in which cancer cells are confined to the upper layer of skin and have not spread. Even men who had taken large quantities of PDE5 inhibitors — about 100 or more pills over the study's time period — had no significant increase in melanoma. The researchers concluded the relationship was not cause and effect, but probably due to an unrelated common factor. One potential explanation is that men prescribed ED drugs are more likely to be seen in the doctor's office, which increases the chance for early melanoma diagnosis.