Vardenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Vardenafil belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. These medicines prevent an enzyme called phosphodiesterase type-5 from working too quickly. The penis is one of the areas where this enzyme works. Erectile dysfunction is a condition where the penis does not harden and expand when a man is sexually excited, or when he cannot keep an erection. When a man is sexually stimulated, his body’s normal response is to increase blood flow to his penis to produce an erection. By controlling the enzyme, vardenafil helps to maintain an erection after the penis is stroked by increasing blood flow to the penis. Without physical action to the penis, such as that occurring during sexual intercourse, vardenafil will not work to cause an erection.