OBJECTIVES To assess the changes in PPI prescriptions dispensed after the introduction of new reimbursement policy from February 1, 2007. The intention of the new policy was to reduce costs by shifting patients from esomeprazole to lansoprazole, omeprazole or pantoprazole. New patients should not start on esomeprazole and ongoing esomeprazole patients should shift to a different PPI. Esomeprazole could be used upfront in severe cases or after having tried a different PPI first. METHODS The Norwegian Prescription Database (NorPD) contains data on all prescriptions dispensed making it possible to follow each individual over time. All PPI prescriptions dispensed from January 1, 2004 to January 31, 2008 were analysed. RESULTS For patients using esomeprazole before February 1, 2007 and having a new PPI prescription dispensed the year after (n=79781), 64% continued on esomeprazole and 36% changed to a different PPI. In the latter group 57%, 20% and 23% shifted to pantoprazole, lansoprazole or omeprazole, respectively. 27%, 23% and 21% of those who shifted from esomeprazole to pantoprazole, lansoprazole or omeprazole, respectively, shifted back to esomeprazole again. The overall figure was 25%. For patients starting on PPI treatment during the year after February 1, 2007 (n=32479), 42% started with pantoprazole, 16% with omeprazole, 19% with lansoprazole and 23% with esomeprazole. Seven percent in the group of new PPI users shifted to a second PPI. There was a profound drop in new prescriptions dispensed for esomeprazole from 57% during the last quarter before the introduction, to 26%, 24%, 22% and 20% during the four quarters after introduction. CONCLUSIONS The new reimbursement policy for PPIs has led to significant changes in the pattern of prescription dispensed. The policy was easier to implement for new patients starting on PPI treatment compared to a compulsory shift for patients on ongoing esomeprazole treatment.