During 3 to 6 months of double-blind treatment or longer-term 1 year , open-label studies, few patients withdrew from active treatment for any reason, including lack of effectiveness. In vivo studies: No significant interactions were shown with tolbutamide mg or warfarin 40 mg , both of which are metabolized by CYP2C9. Effects of VIAGRA on Vision: At single oral doses of mg and mg, transient dose-related impairment of color discrimination was detected using the Farnsworth-Munsell hue test, with peak effects near the time of peak plasma levels. These effects on the metabolite are not expected to be of clinical consequence. 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. Shake the liquid well for 10 seconds before each use to mix the medication evenly. Percentage of Patients Reporting an Improvement in Erections.VIAGRA does not protect against sexually transmitted diseases, including HIV. The most common side effects of VIAGRA: headache; flushing; upset stomach; This Savings Offer is limited to 50% savings off the amount of your co-pay or your out-of-pocket cost, whichever is less, with a maximum savings of $ off each prescription for up to The generic is considered to be as safe and effective as the original drug. And generics tend to cost less than brand-name drugs. Sildenafil is available in two brand-name forms. Sildenafil citrate is a white to off-white crystalline powder with a solubility of mg/mL in water and a molecular weight of VIAGRA is formulated as blue, film-coated rounded-diamond-shaped tablets equivalent to 25 mg, 50 mg and mg of sildenafil for oral administration.