On June 30, 2016, the FDA announced that it would investigate the possible link between skin melanomas and erectile dysfunction (ED) drugs such as Viagra, Cialis, and Levitra.
This recent announcement from the FDA Adverse Event Reporting System (FAERS) included all of the following PDE-5 inhibitors:
- Adcirca (tadalafil)
- Cialis (tadalafil)
- Levitra (vardenafil hydrochloride)
- Revatio (sildenafil citrate)
- Staxyn (vardenafil hydrochloride)
- Stendra (avanafil)
- Viagra (sildenafil citrate)
As regards the FAERS, this Medscape article brings up a valid point:
A drug’s appearance on a quarterly FAERS watch list does not mean the FDA has determined there is a cause-and-effect relationship between the drug and the cited adverse event. Instead, the agency evaluates the need for regulatory action. If its investigation uncovers a causal link, the agency could gather more information to better describe the threat, revise the drug’s label, require a Risk Evaluation and Mitigation Strategy, or in extreme cases, pull the drug from the market.
However, the article from the Journal of the American Medical Association, “Use of Phosphodiesterase Type 5 Inhibitors for Erectile Dysfunction and Risk of Malignant Melanoma,” notes that for melanoma, “the risk estimates were similar for sildenafil and vardenafil or tadalafil.”
Additionally, they performed a separate analysis of men who only ever used Viagra, and those who only used Cialis or Levitra. The results are listed in the table, below:
The researchers note that “the association with melanoma was similar for the 3 PDE5 inhibitors…[and] there was a statistically significant association with melanoma in men who used sildenafil only (OR, 1.26 [95% CI, 1.08-1.48]) and vardenafil or tadalafil only (OR, 1.30 [95% CI, 1.08-1.57]).”
While there seem to be more studies readily available concerning the relationship between melanoma and Viagra (sildenafil), the article “Sildenafil use and increased risk of incident melanoma in US men: a prospective cohort study” states that this may be due to the fact that researchers “did not have the information on other PDE5A inhibitors because neither vardenafil (Levitra) nor tadalafil (Cialis) had been approved by FDA in 2000.” They go on to state that “the observed association between sildenafil use and melanoma might be partly attributed to the later use of vardenafil and tadalafil among recent sildenafil users.”
Lastly, the article “Sildenafil Potentiates a cGMP-Dependent Pathway to Promote Melanoma Growth“ warns that “the use of sildenafil (Viagra) or other PDE5 inhibitors like vardenafil (Levitra) or tadalafil (Cialis) could promote melanoma in humans.” This article later states that “Dynamic cGMP measurements in living 1205Lu cells confirmed these results and showed that in addition to sildenafil, cGMP signals were also enhanced by two other clinically used PDE5 inhibitors, tadalafil and vardenafil.”
While the main legal focus is currently on the relationship between Viagra and melanoma skin cancer, more lawsuits concerning those who have taken Cialis and Levitra and been diagnosed with melanoma should be filed in the near future, based on the aforementioned research.
As such, we will continue to monitor the medical literature concerning Viagra, Cialis, and Levitra, and their link to melanoma skin cancer.
Written by: Heather Helmendach, Legal Assistant
Law Offices of Thomas J. Lamb, P.A.
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