It continues to work for up to 4 hours, although its action is usually less after 2 hours. Erectile dysfunction is a condition where the penis does not harden and expand when a man is sexually excited, or when he cannot keep an erection. If you prefer, you may contact the U. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail. 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. Stop taking VIAGRA and call your healthcare provider right away if you have any sudden vision loss sudden hearing decrease or hearing loss. Click here for an email preview.Sildenafil oral tablet is available as the brand-name drugs Viagra and Revatio. It’s also available as a generic drug. Generic drugs usually cost less than the brand-name . Sildenafil oral tablet is available as the brand-name drugs Viagra and Revatio. It’s also available as a generic drug. Generic drugs usually cost less than the brand-name . AdWith RexMD you’re saving time and money with our Viagra delivery. Get started now. Reliable E.D. meds prescribed by real doctors. Get your free & private online visit today10K+ visitors in the past monthFree Shipping · Discreet Packaging · Real Doctors · Personalized PlanTypes: Sertraline · Erectile Dysfunction · Testosterone · Genital Herpes.