Children 1 year of age and older weighing 20 kg or less—10 mg 3 times a day. This medicine also works best when you take it an hour before sex on an empty stomach. Try nicotine replacement, such as over-the-counter gum or lozenges, or ask your doctor about a prescription medication that can help you quit. These products are especially dangerous for anyone who takes nitrates. Sildenafil may cause side effects. Do not take a double dose to make up for a missed one. 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.Sildenafil oral tablet is used to treat erectile dysfunction (ED). It’s also used to treat pulmonary arterial hypertension (PAH). What is sildenafil? Sildenafil is a prescription. Before taking any medication for erectile dysfunction, including over-the-counter supplements and herbal remedies, get your doctor’s OK. Medications for erectile . Sildenafil is used to treat male sexual function problems (impotence or erectile dysfunction-ED). In combination with sexual stimulation, sildenafil works by increasing .