Sildenafil comes as a tablet and suspension liquid to take by mouth. The pattern of responses was similar for the other principal question, the ability to achieve an erection sufficient for intercourse. Percentage of Patients Reporting an Improvement in Erections. 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 side effects include headache, facial flushing, indigestion, and dizziness. They have the same benefits and risks as their brand-name counterparts. In vivo studies: No significant interactions were shown with tolbutamide mg or warfarin 40 mg , both of which are metabolized by CYP2C9. · You can take the drug 30 minutes to 4 hours before you anticipate sexual activity. Based on how well you respond to this dosage and any side effects you have, your doctor may either increase your. Sildenafil oral tablet is available as a brand-name drug and as a generic drug. Brand names: Viagra, Revatio. Sildenafil comes in three forms: an oral tablet, an oral suspension (liquid), and an. In , a meta-analysis of trials determined that while Viagra is the most effective of the various ED drugs on the market, it also has the highest incidence of side effects—headache, upset stomach, vision loss, blue-tinged sight, back pain, muscle pain, nausea, and dizziness, just to name a few common ones.