Erectile dysfunction is one of the most notorious sexual disorders of men. Fortunately, Pfizer pharmaceuticals came up with a wonder drug in the beginning of 21th century popularly known as Viagra. It, in the case of erectile dysfunction, increases the blood flow to penis significantly and causes the impotence to go away giving the patient more than enough erection. Viagra is a top selling blockbuster drug to enhance libido.

Initially, it was experimented for its beneficial effects on the disorder of angina, heart attack. Later on, scientists discovered remarkable effect of Viagra to increase penile erection in an already stimulated person. Thus, It was further refined for its administration for the treatment of impotence and erectile dysfunction.

Chemically composed of sildenafil citrate, Viagra is a potent inhibitor of PDE5, a cGMP catabolizing enzyme found abundantly in lungs and especially in penile tissues. The drug, by its competitive inhibition of PDE5, increases the level of cGMP, a potent smooth muscle relaxant produced by guanylate cyclase enzyme of the body when coupled with appropriate NO production upon sexual stimulation. Vascular smooth muscle relaxation of the penile blood vessels leads to their vasodilatation and increased blood flow to penis. High blood quantity in penis causes erection thus relieves the organ of impotence and insensitiveness.

Due to its successful therapeutic effects, it has become a permanent choice of adult community and others as a perfect enhancement of their sexual needs related to recreation. Other uses of the drug include treatment for pulmonary arterial hypertension and in sports. It is seen to reduce the post ejaculatory refractory period for better sexual experiences. Detailed research has revealed that the drug also improves sexual performance in females taking antidepressants on part of its effect of increasing blood flow to genitals.