Take sildenafil as needed before sexual activity. 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. To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and site usage information with other information we have about you. Do not mix the liquid with other medications or add anything to flavor the medication. Recent heart or blood vessel problems. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. · Description and Brand Names. Drug information provided by: Merative, Micromedex® US Brand Name. Revatio; Viagra; Descriptions. Sildenafil is used to treat . Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes . Do not take sildenafil with any other product that contains sildenafil or other similar medications for erectile dysfunction-ED or pulmonary hypertension (such as tadalafil, .