About sildenafil Viagra Sildenafil is a medicine used to treat erection problems erectile dysfunction. The primary measure in the principal studies was a sexual function questionnaire the International Index of Erectile Function – IIEF administered during a 4-week treatment-free run-in period, at baseline, at follow-up visits, and at the end of double-blind, placebo-controlled, at-home treatment. If you’re not sure if you’re taking a nitrate, ask your doctor or pharmacist. The concomitant use of erythromycin or strong CYP3A4 inhibitors e. This site is intended only for U.The generic name for Viagra is sildenafil. The drug also has another brand name: Revatio. It works by slowing down the action of PDE5, an enzyme in the blood vessel walls.. This enzyme breaks down. VIAGRA is supplied as blue, film-coated, rounded-diamond-shaped tablets containing sildenafil citrate equivalent to 25 mg, 50 mg, or mg of sildenafil. Tablets are debossed with PFIZER on one side and VGR25, VGR50 or VGR on the other to indicate the dosage strengths. Close. No hay productos en mi carrito Total del pedido: € Español.