Viagra Is Associated With A Higher Incidence Of Invasive Melanoma; This Side Effect May Apply Also To Cialis and Levitra, Two Other Popular ED Drugs
(Posted by Tom Lamb at DrugInjuryWatch.com)
Viagra (sildenafil), the most common drug prescribed for male erectile dysfunction (ED), appears to increase the risk for invasive melanoma but not cutaneous squamous cell carcinomas nor basal cell carcinomas.
Essentially, Viagra acts by inhibiting phosphodiesterase 5 (PDE5). Experimental in vitro studies show that PDE5 inhibition augments tumor cell invasiveness, supporting this new Viagra side effect finding.
From the Abstract for the underlying medical journal article, "Sildenafil Use and Increased Risk of Incident Melanoma in US Men: A Prospective Cohort Study", published by JAMA Internal Medicine in April 2014 (as an Online First item):
- Importance The RAS/RAF/mitogen-activated protein kinase and extracellular signal–regulated kinase (ERK) kinase/ERK cascade plays a crucial role in melanoma cell proliferation and survival. Sildenafil citrate (Viagra) is a phosphodiesterase (PDE) 5A inhibitor commonly used for erectile dysfunction. Recent studies have shown that BRAF activation down-regulates PDE5A levels, and low PDE5A expression by BRAF activation or sildenafil use increases the invasiveness of melanoma cells, which raises the possible adverse effect of sildenafil use on melanoma risk.
- Objective To evaluate the association between sildenafil use and risk of incident melanoma among men in the United States.
- Conclusions and Relevance Sildenafil use may be associated with an increased risk of developing melanoma. Although this study is insufficient to alter clinical recommendations, we support a need for continued investigation of this association.
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At the PubMed Commons part of the page where this April 2014 JAMA Internal Medicine article is found on PubMed.gov (U.S. National Library of Medicine) we found this Comment by David L. Keller, MD, MS, that has to do with Cialis and Levitra, two other popular ED drugs:
Sildenafil (Viagra) was associated with increased risk of melanoma in this study, and a plausible biological mechanism was proposed to explain this association. Two other closely-related phosphodiesterase inhibitors are widely used: tadalafil (Cialis) and vardenafil (Levitra); are these drugs also associated with increased risk of melanoma? One would expect this association to be a class effect.
The results of this study will be of particular concern to men who have used sildenafil and may be at elevated risk of melanoma due to history of extensive sun exposure, basal or squamous cell skin cancers, Parkinson disease (which causes autonomic erectile dysfunction and is associated with elevated risk of melanoma) or family history of melanoma....
We will continue to monitor this emerging drug safety issue concerning an increased incidence of melanoma in men who use Viagra, which may also apply to users of Cialis or Levitra, as well.