Sildenafil (Viagra) Tadalafil (Adcirca, Cialis) Vardenafil (Levitra, Staxyn) Avanafil (Stendra) All four medications enhance the effects of nitric oxide — a natural .If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. Children 1 year of age and older weighing 20 to 45 kg—20 mg 3 times a day. Sexual activity may be a strain on your heart, especially if you have heart disease. Are you anxious, depressed or under stress? Here are some steps that might help: If you smoke, quit. But we get it — talking about ED is uncomfortable. Sildenafil may cause side effects.Why is this medication prescribed? Sildenafil (Viagra) is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Viagra basics The active drug in Viagra is sildenafil. It belongs to a group of drugs called phosphodiesterase-5 inhibitors. Viagra comes as tablets you take by mouth. . Sildenafil (Viagra) Tadalafil (Adcirca, Cialis) Vardenafil (Levitra, Staxyn) Avanafil (Stendra) All four medications enhance the effects of nitric oxide — a natural .Visiting a specialist Sometimes ED is a symptom of an underlying condition. And what about drugs that decrease the effect of Viagra on your erections? Some medications should not be taken with sildenafil. This is a type of high blood pressure that occurs between the heart and the lungs. Erectile dysfunction care at Mayo Clinic Our caring team of Mayo Clinic experts can help you with your health concerns. The thing is, erectile dysfunction is a lot more common than people think.