Have been on Prevacid for the past 5 years. Seemed to stopped working around Nov of last year. Endoscopy revealed gastritis, not ulcers also H pylori.a round of antibiocs fixed this( pepcid and zantac during this period) afterwards was put on Proton. I have not found anything that has stopped this acid reflux, although now that I am taking Prevacid in the am and occasional zantac, up to twice a day, it seems to help. I am not about to pay the insurance premium for the Nexium. You could alwasy try the prevacid along with the zantac? If this does not work, go back to the Nexium. My gastro suggest the others way before he suggest Nexium. Says its a pharmaceutical rip off!