Storage Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. If your dose is different, do not change it unless your doctor tells you to do so. Shake the liquid well for 10 seconds before each use to mix the medication evenly. If you are a Mayo Clinic patient, this could include protected health information. If you become pregnant while taking sildenafil, call your doctor. What special precautions should I follow?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 .  · Adults 65 years of age and older—25 mg as a single dose no more than once a day, 1 hour before sexual intercourse. Alternatively, the medicine may be taken .  · US Brand Name Revatio Viagra Descriptions Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil belongs to a .