Store mixed oral liquid in the refrigerator. Ask your doctor if you have any questions. Children—Use is not recommended. The body takes longer to absorb it after a high-fat meal or alcohol. Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases.swelling in your hands, ankles, or feet; shortness of breath; seizure (convulsions); or. a light-headed feeling, like you might pass out. Common Viagra side effects may include: flushing (warmth, redness, or tingly feeling); headache, dizziness; abnormal vision (blurred vision, changes in color vision) runny or stuffy nose, nosebleeds;. Sildenafil is used to treat erectile dysfunction (ED) and to reduce blood pressure in pulmonary arterial hypertension (PAH). It is taken when needed for ED and daily for PAH. A headache, stomach upsets, and flushing are the main side effects, and it should not be taken within 24 hours of a nitrate. 5. Tips. Sildenafil is available through Roman by prescription in , , mg pills and ranging in price from $4–$10 per dose. Brand-name Viagra is also available through Roman in , , mg.