Viagra is a popular drug that was first approved by the FDA in 1998 to treat male impotence. The drug was patented in 1996 and became the first approved oral erectile dysfunction treatment sold in the United States. Pfizer, the company that markets Viagra, filed a patent for Viagra, also known as sildenafil, in 1992. This patent expired in 2012. Therefore, generic versions of the drug have been available from various manufacturers since 2013. Pfizer’s patent has also expired in many EU countries such as France, Italy, Spain, the United Kingdom and Ireland, as well as in Brazil. In many countries where Pfizer’s patent claim either does not apply or is not strictly enforced, it may be possible to obtain what is known as generic Viagra. These countries include China, Egypt and India.