Do not take more or less of it or take it more often than prescribed by your doctor. Do not stop taking sildenafil without talking to your doctor. What special precautions should I follow? Stop taking VIAGRA and call your healthcare provider right away if you have any sudden vision loss sudden hearing decrease or hearing loss. Alpha-blockers are sometimes prescribed for prostate problems or high blood pressure. Sildenafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow easily. This site is intended only for U.Viagra comes in these strengths: 25 milligram (mg), 50 mg, and mg. Other forms of sildenafil (the active drug in Viagra) comes in other strengths, such as 20 mg. But Viagra only comes in the. According to price-comparison site test1.ru, generic Revatio will cost you as little as $ per pill, depending on where you fill your prescription. That’s compared with . 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.