Zenegra is a generic Sildenafil-containing medicine intended for use in urology – for the most part in the treatment of erectile dysfunctions of different origin. The drug provides regulation of the enzymic activity of the specific phosphodiesterase and releases nitric oxide that provides the muscle-relaxing effect. The active ingredient also maintains a certain level of blood pressure in the penis, providing a proper erectile response. The usual effect lasts no less than 4 hours; however, some patients report 18 and more hours of increased sexual arousal.