Children—Use is not recommended. An inherited eye disease that affects the retina. Follow your doctor’s orders or the directions on the label. It is not known if the medicine is safe for use in these patients. Children 1 year of age and older weighing 20 kg or less—10 mg 3 times a day.Find patient medical information for Viagra oral on MD including its uses, side effects and safety, interactions, pictures, warnings and user ratings. Typical dosing for Sildenafil (Viagra) The typical dose is to take 50 mg of sildenafil (Viagra) by mouth, about 1 hour before sex, as needed. The maximum recommended dose is . Viagra comes as tablets that you take by mouth, when needed. Available strengths: 25 mg, 50 mg, mg. Viagra comes in these strengths: 25 milligram (mg), 50 mg, and mg.