People with heart conditions should never take ED medications without consulting a doctor. However, the dose is usually not more than 80 mg 3 times a day. Make sure to get an estimate of when you can expect your prescription in the mail. Vardenafil usually works for 4 to 5 hours. 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. Common ones include: Flushing of the skin. · Maintenance: 25 to mg orally once a day, as needed, 1 hour prior to sexual activity Comments: This drug may be taken anywhere from 30 minutes to 4 hours before sexual activity. Use: Treatment of erectile dysfunction. Usual Adult Dose for Pulmonary Hypertension. Revatio (R): Oral: Initial dose: 5 or 20 mg orally three times a . Viagra comes as an oral tablet in different dosages. Discuss with your doctor what’s an appropriate dose for you. For daily use, Goldstein said, the generic form, sildenafil, comes in mg tablets. Cost: Consultation prices vary based on the prescriber; $5 generic prescriptions Medical Consultation Required: Yes Medications Prescribed: Viagra, Cialis, sildenafil, tadalafil .