Levitra (vardenafil) belongs to a class of medications called phosphodiesterase (PDE) inhibitors. Vardenafil relaxes muscles found in the walls of blood vessels and increases blood flow to particular areas of the body. Levitra works by increasing blood flow to the penis during sexual stimulation. This increased blood flow can cause an erection. Levitra is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Levitra does not cure erectile dysfunction or increase sexual desire. This medicine does not prevent pregnancy or the spread of sexually transmitted diseases such as human immunodeficiency virus (HIV).