Viagra (Sildenafil citrate) is a drug used to treat erectile dysfunction (impotence) in males and pulmonary arterial hypertension (PAH).
The pharmaceutical company, Pfizer, originally developed Viagra. In 1006, the FDA approved Viagra as the first drug patented for use of erectile dysfunction in the United States. They are blue, diamond-shaped pills with “Pfizer” marked on one side and “VGR XX.” The XX is the dosage, which is either 25,50, or 100 mgs. Viagra is also sold under the brand name Revatio and generically under various other names. It is also widely availabe by many research companies and underground labs.
Viagra treats erectile dys function and works by 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. The most common side effects of Viagra are headache, facial flushing, and upset stomach. Rarely, blurred vision, or sensitivity to light may briefly occur.
As well as treating impotence, Sildenafil Citrate can also be effective in treating Pulmonary Arterial Hypertension (PAH). Similarly to how it acts to relax muscles of the penis, it relaxes arterial walls; therefore, reducing resistance and pressure in the arteries.
Sildenafil Citrate 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.