Children younger than 1 year of age—Use and dose must be determined by your doctor. When oral medications might not be safe Check with your health care team before you take any medicine for erectile dysfunction. If you experience a sudden loss of vision in one or both eyes, contact your doctor immediately. Do not start these medications while taking sildenafil without discussing it with your healthcare provider. This increased blood flow can cause an erection. Dosing The dose of this medicine will be different for different patients.Sildenafil (Viagra) is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. 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 hypertension (PAH; high blood pressure in the vessels carrying blood to the . · For treatment of erectile dysfunction: For oral dosage form (tablets): Adults up to 65 years of age—50 milligrams (mg) as a single dose no more than once a day, 1 hour before sexual intercourse. Alternatively, the medicine may be taken 30 minutes to 4 hours before sexual intercourse. Your doctor may adjust your dose if needed. Viagra is effective because it slows the action of phosphodiesterase type 5 (PDE5), an enzyme in the blood vessel walls. This helps the muscles in the penis to relax and encourage blood flow.
