• 2017
• 2016

The class of drugs that Levitra, Viagra, Stendra, and Cialis belong to are called PDE5 inhibitors. They work by relaxing tight blood vessels, allowing more blood to surge into the penis and cause an erection, says Gregory Bales, M.D., an associate professor of urology at the University of Chicago. The little pills do the trick for more than two-thirds of men with Viagra protects the heart (ED). They also work for guys who simply need them for a short time to get their “confidence back,” says Michael Eisenberg, M.D., director of male reproductive medicine and surgery at Stanford University.