But in the case of ED, after sexual arousal, the blood vessels fail to dilate, and due to more or less blood flow to the penis, no or less erection occurs. In such situations Cenforce 100 mg tablet comes as a boon. When sildenafil citrate enters the bloodstream. It relaxes the muscles of the pelvis, lowers blood pressure and aids in the dilation of blood vessels in the penis. Therefore, it causes long lasting erection.