Other contraindications include hypersensitivity to any component of the formulation, pulmonary veno-occlusion, left ventricular outflow obstruction, PAH associated with sickle cell anemia, and multiple system atrophy. Describe the clinically important drug interactions of sildenafil. It is important to tell your doctor about any heart problems you have now or may have had in the past. Children 1 year of age and older weighing 45 kilograms kg or more—20 mg 3 times a day. Patients should always ask their doctors for medical advice about adverse events.Sildenafil is used to treat high blood pressure in the lungs (pulmonary hypertension). Learn more about Revatio. 1. This is a generic drug. The average cost for 30 Tablet(s), mg each of the generic (sildenafil citrate) is $ You can buy sildenafil citrate at the discounted price of $ by using the MDRx coupon, a savings of 43%. Prices for Sildenafil (Revatio) are as low as $ with a GoodRx coupon. There is usually no benefit to taking more than 20 mg 3 times a day, though some medical specialists will recommend higher strengths (still taken 3 times a day). White Round R And 20 – Sildenafil Citrate 20mg Tablet. This medicine is White, Round Tablet . Sildenafil is available through Lemonaid by prescription in mg pills for $2 per dose. Hims and Roman doses of sildenafil begin at 25 mg, which means that Lemonaid may be an option for people.