There are many safe, reliable online services offering ED prescriptions. 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. Do not stop taking sildenafil without talking to your doctor. That’s not to say there aren’t just as many illegitimate sites. 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. Do not drink grapefruit juice if you’re taking sildenafil Revatio for pulmonary hypertension.Sildenafil (Viagra) is a medicine used to treat erectile dysfunction (ED, also called impotence). Sildenafil works by helping to relax the blood vessels in the penis, allowing more blood to flow in and cause an erection. You should take sildenafil about an hour before planned sexual activity, so it has time to work. Medications Prescribed: Viagra, Cialis, Cialis Daily, Levitra, tadalafil, sildenafil, vardenafil. Generic offered: Yes. Why We Chose It. The simple combination of Rex MD’s online platform, its helpful customer service, and the abundance of ED treatment options make it a one-stop shop for all your sexual health needs.  · Maximum dose: 20 mg orally three times a day. Injection: Initial dose: or 10 mg IV bolus three times a day. Comments: No greater efficacy was achieved with oral doses higher than the maximum recommended dose. A 10 mg injection dose is predicted to provide pharmacological effect equivalent to the 20 mg oral dose.