Do not use a kitchen teaspoon as it will not measure the right amount. Describe the clinically important drug interactions of sildenafil. Never take an extra dose to make up for a forgotten one. The effects may be increased because of slower removal of the medicine from the body. Children 1 year of age and older weighing 20 kg or less—10 mg 3 times a day. Proper Use Use sildenafil exactly as directed by your doctor. For treatment of pulmonary arterial hypertension: For oral dosage forms suspension or tablets : Adults—20 milligrams mg 3 times a day. · Detailed Sildenafil dosage information for adults and the elderly. Includes dosages for Erectile Dysfunction and Pulmonary Hypertension; plus renal, liver and dialysis adjustments. Initial dose: 50 mg orally once a day, as needed, 1 hour prior to sexual activity Maintenance: 25 to mg orally once a day, as needed, 1 hour prior to sexual. Sildenafil tablets for pulmonary hypertension come in 10mg and 20mg strengths. The usual adult dose is 20mg taken 3 times a day. Doses for children can range from 10mg to 20mg taken 3 times a day, depending on their weight. Do not take it more than 3 times a day. 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 sexual activity. It can be taken