Tadalafil
Tadalafil is an orally administered drug used to treat male erectile dysfunction (impotence). It is marketed worldwide under the brand name Cialis. and Erectile dysfunction is a condition where the penis does not harden and expand .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, tadalafil helps to maintain an erection after the penis is stroked by increasing blood flow to the penis.