Viagra comparison to cialis and levitra

Stendra Compared to Viagra and Cialis for ED Treatment - Prostate. Jun 19, 2012. The five FDA-approved erectile dysfunction drugs on the market are avanafil Stendra, sildenafil Viagra, tadalafil Cialis, and vardenafil both Levitra and Staxyn, an orally dissolving form of Levitra. All of these drugs belong to the same drug class known as phosphodiesterase PDE inhibitors because....