They’re often the first line of treatment for trouble getting or keeping an erection, called erectile dysfunction ED. Severe liver disease. If you are a Mayo Clinic patient, this could include protected health information. Sildenafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow easily. Sorry something went wrong with your subscription Please, try again in a couple of minutes Retry. · Viagra; Descriptions. Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil belongs to a group of medicines Missing: explained. Sildenafil (Liqrev, Revatio) is used to improve the ability to exercise in adults (Liqrev, Revatio) and children 1 year of age and older (Revatio) with pulmonary arterial Missing: explained. Sildenafil (Viagra). This medicine works best when you take it on an empty stomach an hour before sex. The body takes longer to absorb it after a high-fat meal or .