Sorry something went wrong with your subscription Please, try again in a couple of minutes Retry. Side effects Side effects of oral ED medicines are often mild. If you ever need emergency medical treatment for a heart problem, the healthcare providers who treat you will need to know when you last took sildenafil. If you experience chest pain, dizziness, or nausea during sexual activity, call your doctor immediately and avoid sexual activity until your doctor tells you otherwise. As with sildenafil, a high-fat meal or alcohol keep the body from absorbing it as quickly. Your doctor may need to change the doses of your medications or monitor you carefully for side effects. · Take sildenafil exactly as it was prescribed for you. Follow all directions on your prescription label and read all medication guides or instruction sheets. Revatio is . On this page Highlights for sildenafil Sildenafil oral tablet is available as a brand-name drug and as a generic drug. Brand names: Viagra, Revatio. Sildenafil . Products and services Erectile dysfunction: Viagra and other oral medications By Mayo Clinic Staff Medicines that you take by mouth are called oral .