Buy Fildena 120mg Online belongs to a group of medicaments known as PDE5 inhibitors. In order to understand exactly how the medication works it is necessary to understand the physiological mechanism of erection. After the s**ual arousal, nitrogen oxide is released in the corpus cavernous body of the pe**is. After release Nitrogen oxide actives the enzyme called guanylate cyclase leading to synthesis of cyclic GMP or cGMP. Cyclic GMP ineracts wit hthe smooth muscles of the cavernous body causing them to relax.