Active ingredient: vardenafil HCl
Other Ingredients: microcrystalline cellulose, crospovidone, colloidal silicon dioxide, magnesium stearate, hypromellose, polyethylene glycol, titanium dioxide, yellow ferric oxide, and red ferric oxide.
Class and mechanism: Erection of the penis is initiated by the relaxation of smooth muscle in the corpus cavernosum, one of a pair of sponge-like regions in the penis. When aroused, nitric oxide is released from nerve endings and endothelial cells in the corpus cavernosum. Nitric oxide activates the enzyme guanylate cyclase resulting in increased synthesis of cyclic guanosine monophosphate (cGMP) in the smooth muscle cells of the corpus cavernosum. The cGMP triggers smooth muscle relaxation, increasing blood flow into the penis, resulting in erection.