· Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil belongs to a group of medicines called phosphodiesterase .If you have certain health conditions or are taking certain medications, your doctor may tell you to take sildenafil less often. Do not mix the liquid with other medications or add anything to flavor the medication. Your doctor will tell you not to take sildenafil if you are taking street drugs containing nitrates. When hypertension occurs in the lungs, the heart must work harder to pump enough blood through the lungs. Take sildenafil at around the same times every day. Sildenafil is also used in both men and women to treat the symptoms of pulmonary arterial hypertension.Sildenafil oral tablet is available as a brand-name drug and as a generic drug. Brand names: Viagra, Revatio. Sildenafil comes in three forms: an oral tablet, an . By Ginger Skinner Last updated: June 14, If you’re looking for a less costly Viagra, you might want to ask your doctor about sildenafil. It’s the active . Sildenafil is in a class of medications called phosphodiesterase (PDE) inhibitors. Sildenafil treats erectile dysfunction by increasing blood flow to the penis during sexual .Sildenafil does not prevent pregnancy or the spread of sexually transmitted diseases such as human immunodeficiency virus HIV. Sildenafil Viagra is used to treat erectile dysfunction impotence; inability to get or keep an erection in men. Ask your pharmacist or doctor for a copy of the manufacturer’s information for the patient. If you are a Mayo Clinic patient, this could include protected health information. Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Make sure you have discussed any other medications you are currently taking or plan to take before starting sildenafil with your doctor and pharmacist. Erectile dysfunction is a condition where the penis does not harden and expand when a man is sexually excited, or when he cannot keep an erection.