Vardenafil usually works for 4 to 5 hours. If you are taking sildenafil for erectile dysfunction, your doctor will probably start you on an average dose of sildenafil and increase or decrease your dose depending on your response to the medication. These include a heart attack, stroke or a serious heart rhythm disorder in the past six months. They’re often the first line of treatment for trouble getting or keeping an erection, called erectile dysfunction ED. Take sildenafil exactly as directed. 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 lungs, causing shortness of breath, dizziness, and tiredness. This increased blood flow can cause an erection.Do not take Viagra more than once per day. Shake the oral suspension (liquid) before you measure a dose. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon). Viagra can help you have an erection when sexual stimulation occurs. An erection will not occur just by taking a pill. Follow your doctor’s. Your doctor won’t recommend your Viagra dosage by weight. But they may recommend a lower dose of the drug if you’re older than 65 years. This is because you may have an increased risk of side. Viagra is used to treat erectile dysfunction (impotence) in men. Another brand of sildenafil is Revatio, which is used to treat pulmonary arterial hypertension and improve exercise capacity in men and women. This page contains specific information for Viagra, not Revatio.