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 hypertension PAH; high blood pressure in the vessels carrying blood to the lungs, causing shortness of breath, dizziness, and tiredness. Brand names Why is this medication prescribed? Medicines that you take by mouth are called oral medicines. You can take sildenafil with or without food. Generic versions of sildenafil, vardenafil and tadalafil are available.Find patient medical information for sildenafil oral on MD including its uses, side effects and safety, interactions, pictures, warnings and user ratings.  · Viagra is classified as a phosphodiesterase type 5 (PDE5) inhibitor. For information on the dosage of Viagra, including its pill form, strengths, and how to take the drug, keep reading. For a. Strengths: 25 mg, 50 mg, mg; Brand: Viagra. Form: oral tablet; Strengths: 25 mg, 50 mg, mg; Adult dosage (ages 18–64 years) Typical dosage: 50 mg, taken as needed about 1 hour before.