Before taking sildenafil, tell your doctor and pharmacist if you are allergic to sildenafil, any other medications, or any of the ingredients in sildenafil tablet or suspension. VIAGRA was evaluated primarily at doses of 25 mg, 50 mg and mg in 21 randomized, double-blind, placebo-controlled trials of up to 6 months in duration, using a variety of study designs fixed dose, titration, parallel, crossover. Concomitant administration of strong CYP3A4 inducers, such as rifampin, is expected to cause greater decreases in plasma levels of sildenafil. Sildenafil treats erectile dysfunction by increasing blood flow to the penis during sexual stimulation. If you prefer, you may contact the U. As in the other titration studies, patients were started on 50 mg and allowed to adjust the dose up to mg or down to 25 mg of VIAGRA; all patients, however, were receiving 50 mg or mg at the end of the study. How should this medicine be used?If your pharmacy does not participate, you may be able to submit a request for a rebate in connection with this Savings Offer. Pay for your VIAGRA prescription and mail copy of original pharmacy receipt (cash register receipt NOT valid) with product name, date, and amount circled to: VIAGRA Savings Offer, Perimeter Park Drive, Suite  · 86% average discount. Hypertension. 74% average discount. Urinary Tract Infection. 67% average discount. Based on the average user savings between January . Sildenafil is a generic drug, which is an exact copy of the active drug in a brand-name medication. The generic is considered to be as safe and effective as the original drug. And generics tend to.