Pharmaceutical

Pfizer seeks to expand Viagra sales to over-the-counter

Viagra single pack Pfizer seeks to expand Viagra sales to over the counterAccording to the Pharmaceutical Journal, Pfizer, the manufacturer of erectile dysfunction (ED) drug Viagra (sildenafil) has set its sights on having the drug, which has been prescribed for more than 64 million men worldwide, available over-the-counter as well.

Ten years ago Pfizer applied to the European Medicines Agency (EMA) for non-prescription status of Viagra, but the agency had concerns that in bypassing the need for a prescription from a general practitioner (GP), men whose symptoms would have led to diagnosis of cardiovascular disease might self-diagnose and treat ED symptoms over-the-counter, missing the underlying more serious disease. The agency also expressed concern over the potential spike in recreational use of Viagra that might result from changing its availability in this way.

Now Pfizer is trying again, nearly 20 years after the drug was licensed as the first oral medicine to treat erectile dysfunction. UK drugs regulator the Medicines and Healthcare products Regulatory Agency (MHRA) is considering making sildenafil 50mg tablets available in all UK pharmacies without a prescription.

It is suggested that Viagra that can be obtained over-the-counter without a visit to the GP might compete with the illicit counterfeit ED drugs that are available without prescription over the internet. These dangerous unregulated drugs put the men who purchase them at risk. Another suggested benefit is that more men who suffer from ED might be willing to seek treatment. It is certainly likely to boost sales of the drug, which accounted for more than $1.8 billion of Pfizer’s revenue in 2013 according to its annual report.

The Pharmaceutical Journal points out that reclassifying sildenafil “would not be such a huge leap.” In 2007, the pharmacy Boots began to offer the drug through a private patient group direction (PGD) in which eligible men are allowed to purchase medicines without a prescription because their doctor and pharmacist have formed an agreement. Since then other pharmacies have offered Viagra as well as other phosphodiesterase-5 (PDE-5) inhibitors through PGDs.

In this scenario, the burden lies with the pharmacists to determine if sildenafil is safe for every patient who has self-diagnosed and come in for ED treatment. The Pharmaceutical Journal says, “training may be needed to help pharmacists recognise patients who could be suffering from underlying cardiovascular disease, depression, anxiety and alcohol use, and to counsel, support, and refer these patients appropriately.” Pharmacists will be the sole ones responsible for observing drug interactions, risks and situations where sildenafil might be harmful to a patient.

The MHRA is evaluating the feedback from the public consultation on the possible reclassification that ran from March 27 to April 18 and has not yet reached a decision.

Meanwhile, the United States’ regulatory agency, the U.S. Food and Drug Administration announced last year that it was investigating the association between Viagra and other PDE-5 inhibitors and melanoma, the most deadly form of skin cancer. A number of studies, specifically two large studies published since 2014 have found a statistically significant association between PDE-5 inhibitors and melanoma, one finding that sildenafil users are 84 percent more likely to develop melanoma than men who have not taken the drug.

This month a meta-analysis of all of these studies was published and although it also found a statistically significant association between PDE-5 inhibitors and melanoma, the study claimed that the data analysed did not meet the criteria for causality. Another study, published last year, used in-vitro and murine experiments to identify the mechanism by which PDE-5 inhibitors lead to increased tumor growth. The FDA has yet to announce the results of its investigation.

Sources:
The Pharmaceutical Journal
Righting Injustice
U.S. Food and Drug Administration
U.S. National Library of Medicine National Institutes of Health
MPR
Cell Reports