Disclosed herein are oral dosage forms of colesevelam, or a pharmaceutically acceptable salt thereof, adapted to treat upper gastro-intestinal disorders associated with PPI refractory GERD. Also disclosed are the methods of using these oral dosage forms to treat upper gastrointestinal disorders associated with PPI refractory, or PPI resistant, GERD in a patient in need thereof. The oral dosage forms disclosed herein are adapted for the ascribed uses by being comprised of colesevelam, or a pharmaceutically acceptable salt thereof, in a polymeric matrix comprised of one or more hydrophilic polymers such that the oral dosage form erodes upon encountering gastric fluid and has a gastric retention time of three hours or longer, allowing for an extended period of time for the colesevelam to be released in the upper GI and sequester excess bile.
