Assessment of Zegerid on Esophageal pH in Patients With Barrett's Esophagus

The purpose of this research study is to assess how safe, effective (how well it works), and tolerable (to put up with) the drug Zegerid is in reducing reflux episodes in patients who have both gastroesophageal reflux disease (GERD) and Barrett's esophagus. Zegerid has been approved by the US Food and Drug Administration (FDA) for the treatment of GERD. The investigators hope to learn the effectiveness of Zegerid for reducing the amount of acid reflux patients are experiencing in the esophagus (swallowing pipe).