Viagra

This active ingredient is in Viagra This active ingredient in sildenafil, a PDE-5 inhibitor (phosphodiesterase type 5 inhibitor). It is a vasodilator substance. How does Viagra work? Viagra works by inhibiting an enzyme in the body that is responsible for the breakdown of cyclic guanine monophosphate (cGMP). During sexual arousal, this substance causes the penile … Viagra for erectile dysfunction