In case you missed it, the U.S. Patent and Trademark Office recently granted the patent for sildenafil citrate, more commonly known as Viagra. The patent was assigned to Pfizer, the same company that makes Viagra, and is valid for a period of 20 years from the date of filing.
While there are still many questions about Viagra, including whether it can effectively be used to treat erectile dysfunction in men and women, most men will recognize the famous blue pill immediately. Its official description in the U.S. Patent and Trademark Office is as follows:
“Sildenafil citrate, chemically known as 1-[[2′-methyl-4′(1H-tetrazol-5-yl)phenyl]methyl]-5-[[2′-methyl-4′-(1H-tetrazol-5-yl)phenyl]methanesulfonic acid monohydrate, is a potent inhibitor of Phosphodiesterase type 5 (PDE-5). PDE-5 is an enzyme that plays a crucial role in breaking down cyclic guanosine monophosphate (cGMP) in nerve endings. When the enzyme breaks down cGMP, it leads to the production of nitric oxide (NO), causing blood vessels in the penile tissues to relax and become engorged with blood. It is well known that an adequate blood supply to the penis is essential for achieving and maintaining an erection. Sildenafil citrate is a competitive inhibitor of PDE-5 and, as a result, increases cGMP levels in the penile tissues and, consequently, the blood flow to the penis. The increase of cGMP also has the beneficial effect of improving the relaxation of the blood vessels in the lungs and other organs, thus increasing their functionality and protecting the body from disease.”
While the 20-year patent protection for Viagra is very exciting news for menopausal women who want to use the drug for improving their sexual performance, it also presents a new problem for pharmaceutical companies that want to develop a generic version of Viagra. As you may recall, the Hatch-Waxman Act was passed by Congress in 1984 and provides for the fast-tracking of generic drug applications. One of the conditions attached to the grant of a patent is that the patent holder cannot enforce the patent against generic drug manufacturers. While this may not be a problem for Pfizer as it stands now, it’s certainly a concern for companies that have to follow suit.
In a nutshell, the problem is that Viagra is such a popular drug that a lot of manufacturers want to get their hands on the treatment for erectile dysfunction. Since the patent expires in exactly five years, anyone can make and sell a generic version of Viagra as soon as the drug is approved by the U.S. Food and Drug Administration (FDA).
Now, if you’ll excuse me, I have a patent to defend. 🙂