Description
Viagra (Sildenafil citrate) is a drug used to treat erectile dysfunction (impotence) in males and pulmonary arterial hypertension (PAH). Viagra treats erectile dys function and works relaxing muscles and increases blood flow to particular areas of the body (in this case, the penis, specifically). Its effects last up to four hours. Viagra is solely active in relaxing muscles and increasing blood flow to the heart, lungs and penis due to PDE-5, yet vasodilation is not increased in other parts of the body.