What is Viagra?

Viagra holds the distinction of being the first oral medication introduced for erectile dysfunction (ED) in the United States. Manufactured by Pfizer and approved by the FDA in 1998 to treat impotence in men, “the little blue pill” instantly became Pfizer’s highest-selling drug. Worldwide, the blockbuster ED drug brought in just under $2 billion for Pfizer in 2013, and doctors continue to write millions of prescriptions for the drug.
Viagra (sildenafil citrate) was conceived as a treatment for chest pain (angina) and pulmonary arterial hypertension – high blood pressure in the vessels that carry blood to the lungs. Clinical trials results showed the drug as a poor choice as a heart medication, but researchers noticed increased erections in men who volunteered for the study. Pfizer resubmitted the drug for approval to treat ED.
Erectile dysfunction affects approximately 40 percent of men by age 40 to some degree and nearly 70 percent of men by age 70, according to the Cleveland Clinic. More than 45 million have taken Viagra.

How Does Viagra Work?

 

PDE5 Inhibitor

Classified as a PDE5 inhibitor, Viagra works by blocking certain enzymes in the body, causing blood vessels to dilate and enhancing blood flow to the penis. In conjunction with sexual stimulation, the drug-induced blood flow aids in producing and maintaining erection.

Sildenafil and Pulmonary Treatment

Sildenafil is also sold under the brand name Revatio in tablet form or oral suspension form. It is approved by the FDA for the treatment of pulmonary arterial hypertension in adults, and works by dilating blood vessels that supply the lungs with blood.