Zenegra Vs. Viagra
Sildenafil, the common denominator in Viagra and Zenegra
The drugs are defined as generic or equivalent when, compared to the medicinal product or "brand medicine", they have the same active ingredient, the same pharmaceutical form, the same dosage and the same route of administration. Generic drugs are drugs in all respects and can be marketed when the branded medicinal product is no longer covered by a patent. The equivalent drug may have the name of the active ingredient followed by that of the manufacturer or a fancy name.
The company that "discovers" a new active ingredient patents it, creating a medicinal specialty with a fancy name. Another pharmaceutical specialty containing the patented active principle cannot be marketed without the permission of the patent holder.
Viagra, or rather its active substance sildenadil, was discovered in the early 90s and got patented by the American company Pfizer, not without certain initial crediting litigations though. Legally, the copyright and exclusive manufacturing rights have been the prerogative of Pfizer for the better part of 20 years that sildenafil has been around. But as of the second decade of our century, the patent for monopolistic production of Viagra started expiring in one country after another. In the U.S., the generic version of the legendary blue pills will not be available for another year, but it is possible to order cheap generic sildenafil from other countries, where their production is totally legal.
Zenegra is one of such generically produced Viagra equivalents having sildenafil citrate as its active component. When the patent coverage expires, any other company, having obtained the authorization from the competent authority, can market the equivalent drug. In the U.S., patent coverage is much longer than in other countries and can last up to 38 years compared to the 20 years set by the European Union. As a result, the placing on the market of equivalents is delayed compared to other countries where patent coverage has a shorter duration.