Being a medicine whose chief ingredient acts as a PDE-5 inhibitor it would inhibit the PDE-5 enzymes. Thus the cyclic guanosine monophosphate (cGMP) is formed which activates the nitric oxide in the blood. Nitric oxide acts as a vasodilator and helps to relax the tissue of the blood vessels. Thus the blood flow in the body is increased. The increased blood flow will help to get erections if stimulated.