Sildenafil, the active ingredient in Cenforce pills, is a phosphodiesterase type 5 (PDE5) inhibitor. Sildenafil increases the release of nitric oxide, which plays an important role in smooth muscle relaxation. This also helps to sustain an erection.
Another PDE-5 inhibitor, avanafil, also helps to improve erectile function. Vardenafil is a medication that works for eight hours. You should not use a PDE-5 inhibitor with a nitrate-containing medication, such as nitroglycerin.