The main purpose of the drug Sildenafil Cenforce is to treat erectile dysfunction (ED), which is defined as the inability to get or keep an erection that is hard enough for sexual activity. The phosphodiesterase type 5 (PDE5) inhibitors, of which this medicine is a member, increase blood flow to the penis during sexual stimulation. Sildenafil, the active component in Cenforce, is also included in the popular ED drug Viagra.