The Sildenafil citrate in this drug, Assurans falls in the category of PDE5-inhibitor medicines. It efficiently works to block the enzyme called phosphodiesterase type 5. Inhibiting this enzyme helps to prevent the degradation of cGMP, which is a vasodilator. The effect of the Assurans drug leads to an increase in the level of cGMP and nitric oxide that helps to dilate the blood vessels and relaxes the muscles, which allows normal blood flow in the body. Under its effect, the heart can pump blood smoothly.