Avaforce100 Mg Avanafil is an oral drug that is used for treating impotence (the inability to attain or maintain a penile erection), also known as erectile dysfunction (ED). It in a class of drug called phosphodiesterase type 5 (PDE5) inhibitor. Avanafil works by helping to increase blood flow into the penis during sexual stimulation. This helps you to achieve and maintain an erection.