After being introduced in 1998, Zenegra 50mg became the most popular treatment for erectile dysfunction issues. Zenegra 50mg contains an active ingredient Sildenafil which is FDA-approved medication used to treat erectile dysfunction problems in men. Zenegra 50mg is a fast-acting medication that can last up to four hours. 50mg tablet 4's has been estimated that around 140 million men worldwide suffers from impotence. In case any dysfunction of male reproductive system, you need to visit to a physician.