What is Viagra?
Top 1 in Top 7 Things to Know About Viagra
Viagra is a brand name (trade name) for the drug sildenafil. Viagra (sildenafil) works by blocking an enzyme called cGMP-specific phosphodiesterase type-5 (PDE-5). This enzyme breaks cGMP, a substance that relaxes smooth muscles. By blocking PDE-5, smooth muscle cGMP levels rise, promoting muscular relaxation and vasodilation (a widening of blood vessels).
PDE-5 levels are high in the penis, lungs, and retina. PDE-5 is also found in the smooth muscle cells of blood vessels and muscles throughout the body. Viagra is a drug used to treat erectile dysfunction (impotence) in men.
