Study Links Viagra to Increased Risk of Melanoma Skin Cancer
Posted in Dangerous Drugs on April 17, 2014
A study published in April 2014 in the Journal of American Medical Association Internal Medicine (“JAMA”) linked the popular erectile dysfunction drug, Viagra, to an increased risk of melanoma, a deadly form of skin cancer. The study analyzed data from more than 25,000 men who participated in the Health Professionals Follow-up Study and found that men who had recently used sildenafil had nearly twice the risk of developing melanoma (hazard ratio 1.84, CI 1.04 – 3.22) after adjusting for other risk factors including age, body mass index, smoking history, number of sunburns, mole counts, hair color, family history of melanoma, sun exposure, and use of other erectile dysfunction treatments. The study only found an increased risk of melanoma – it did not find an increased risk for more common, less dangerous types of skin cancer such as basal cell carcinoma and squamous cell carcinoma.
Researchers have suspected that Viagra, and other drugs in the same class including Cialis and Levitra, may increase the risk of melanoma because the class of drugs (known as phosphodiesterase (PDE) 5A inhibitors) affect the same genetic pathway that allows skin cancer to become more invasive. Although the JAMA study did not look at other PDE5A erectile dysfunction drugs, Dr. Allan Halpern, of Memorial Sloan-Kettering Cancer Center, noted that other erectile dysfunction drugs, such as Cialis and Levitra, work on the same biochemistry and may pose an even greater risk for melanoma because they are longer lasting in the body than Viagra. Dr. Halpern, also commented on the study, “If it really translated into real life, it might amount to as much as one extra melanoma for every 1,000 men per year. That’s a significant number.”
What is Melanoma?
Melanoma, the most serious type of skin cancer, develops in the cells (melanocytes) that produce melanin, the pigment that gives your skin its color. The most common suspected cause of melanoma is exposure to ultraviolet (UV) radiation from sunlight or tanning lamps and beds. Other common risk factors include fair skin, a history of sunburn, having a large number of moles, and family history.
If melanoma is recognized and treated early, it is usually curable. However, if the cancer advances and spreads to other parts of the body, it becomes difficult to treat and can be fatal. Although it is not the most common form of the skin cancer, it causes the most deaths. The National Cancer Institute estimates that there will be 76,100 new cases of melanoma and 9,710 deaths due to melanoma in the U.S. in 2014.
What is Viagra?
Viagra (sildenafil citrate) is a drug manufactured and sold by Pfizer which is used to treat erectile dysfunction. It has also been approved to treat pulmonary hypertension under the brand name Revatio. Viagra was approved in 1998 and quickly became a blockbuster drug. According to IMS prescription and sales data, 8 million Viagra prescriptions were written in 2012 with total sales of about $2 billion.
Viagra belongs to a class of drugs called PDE5 inhibitors, which also includs Cialis (tadalafil) and Levitra (vardenafil). These drugs treat erectile dysfunction by increasing blood flow to the penis. Viagra is meant to be taken 30 minutes before sexual activity and lasts up to four hours.
Sources:
- www.forbes.com
- www.newyork.cbslocal.com
- www.nbcnews.com
- www.skincancer.org
- www.cnn.com
- www.cancer.gov
- Li WQ, Qureshi AA, Robinson KC, Han J. Sildenafil Use and Increased Risk of Incident Melanoma in US Men: A Prospective Cohort Study. JAMA Intern Med. 2014 Apr 7.