This medicine also works best when you take it an hour before sex on an empty stomach. Read our editorial process. Just visit a participating pharmacy. Men who are taking nitrates or nitroglycerin Those with hypotension Men who have heart disease or heart failure ED can be the first sign of other health conditions, including cardiovascular disease and diabetes. Side effects Side effects of oral ED medicines are often mild.Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes . In combination with sexual stimulation, vardenafil works by increasing blood flow to the penis to help a man get and keep an test1.ru drug does not protect against sexually . Viagra, Cialis, Levitra, and Stendra are all in a class of medications called phosphodiesterase type 5 (PDE5) inhibitors. These drugs work by blocking the PDE5 .