While medications for erectile dysfunction can improve men's lives, they may also carry a downside.
Men who take medication to treat erectile dysfunction (ED) may have a slightly higher risk for skin cancer than men who don't take these drugs, a new study found. However, this possible raised risk is small, and researchers aren’t sure it’s due to the drugs at all.
"Physicians should still screen men for melanoma risk, but they do not need to add use of erectile dysfunction drugs to their list of screening criteria,” said lead study author Stacy Loeb, MD, a urologist at NYU Langone Medical Center, in a press release.
Phosphodiesterase type 5 (PDE5) inhibitors are the most commonly prescribed drugs for ED. This drug class includes sildenafil (brand name Viagra) and vardenafil (Levitra). These drugs are thought to work through similar pathways to those used when the body converts healthy skin cells into malignant melanoma (the most serious type of skin cancer).
That's why Dr. Loeb and team wanted to test whether men who took these drugs had a raised risk of melanoma.
Using health care registries in Sweden, Dr. Loeb and team found 4,065 men diagnosed with malignant melanoma between 2006 and 2012. They also looked at about five times as many men of around the same age who were not told they had the skin cancer. These researchers used the Swedish Drug Register to see which men had taken PDE5 inhibitors for ED. ED is marked by a man's inability to get or maintain erection sufficient for satisfying sexual activity.
Of the melanoma patients, 435 men had filled prescriptions for PDE5 inhibitors. Of 20,325 men not diagnosed with melanoma, 1,713 men had taken these drugs.
Men who had filled one prescription for a PDE5 inhibitor had a raised risk of melanoma (an overall higher risk of 21 percent) — compared to men who had never taken the medicine. However, using more PDE5 inhibitors over time did not appear to further raise melanoma risk, Dr. Loeb and team found.
“This possible association of PDE5 inhibitors and melanoma needs to be taken seriously,” said E. David Crawford, MD, professor of surgery and urology at the University of Colorado in Aurora, in an interview with dailyRx News.
The real risk may not be the medicine, but something else these men have in common, Dr. Crawford said.
"Perhaps men who seek drugs such as Viagra, Cialis, or Levitra are more active and spend more time outside and therefore [face more] sun exposure,” Dr. Crawford said.
Dr. Loeb and team found that men who used ED drugs also had a 19 percent higher risk of basal cell carcinoma, another type of skin cancer — compared to those who didn't use PDE5 inhibitors. However, basal cell carcinoma is not thought to develop in the same way as malignant melanoma.
“When used appropriately, erectile dysfunction medications are very effective and improve the quality of life for many men," Dr. Loeb said.
This study was published June 23 in JAMA.
A grant from the Swedish Research Council and funds from the Louis Feil Charitable Lead Trust funded this research. Three of the study authors disclosed conflicts of interest, including Dr. Loeb, who had been paid to speak about a prostate cancer drug made by Bayer, which also markets Levitra.