Using alcohol or tobacco with certain medicines may also cause interactions to occur. Such patients must not apply any out-of-pocket expenses incurred using this Savings Offer toward any government insurance benefit out-of-pocket spending calculations, such as Medicare Part D true out-of-pocket TrOOP costs You are responsible for reporting use of this Savings Offer to any private insurer, health plan, or other third party who pays for or reimburses any part of the prescription filled using this Savings Offer, as may be required. If it is not treated right away, priapism can permanently damage your penis sudden vision loss in one or both eyes. Children—Use is not recommended. Alternatively, the medicine may be taken 30 minutes to 4 hours before sexual intercourse.Brand Names: Revatio, Viagra. Sildenafil is used to treat male sexual function problems (impotence or erectile dysfunction-ED). This is a generic drug. The average cost for 30 Tablet(s), mg each of the generic (sildenafil citrate) is $ You can buy sildenafil citrate at the discounted price of $ by using the MDRx coupon, a. That’s compared with more than $50 per pill for Viagra. And while generic Revatio is available only in a mg strength—Viagra comes in , , and mg tabs—not to worry: Your doctor can.  · For treatment of erectile dysfunction: For oral dosage form (tablets): Adults up to 65 years of age—50 milligrams (mg) as a single dose no more than once a day, 1 hour before sexual intercourse. Alternatively, the medicine may be taken 30 minutes to 4 hours before sexual intercourse. Your doctor may adjust your dose if needed.