The state of Texas Drug Utilization Review (DUR) Board, composed of six physicians and six pharmacists, meets quarterly to determine criteria for implementing retrospective DUR. The board agreed to send intervention letters to physicians concurrently prescribing: (1) two histamine2 (H2)-antagonists (H2As) or (2) either any H2A or omeprazole with sucralfate. To measure the effect of these intervention letters, approximately half of these physicians were randomly chosen to receive a letter while the others served as a control group and did not receive letters. This project focused on the H2A or omeprazole with sucralfate intervention letters in a two-step process. Data on concurrent therapy involving two H2As were analyzed separately and these results are not included in this report. Objective one was to examine feedback from the physicians who received the letters, and objective two was to review and compare patient profiles 6 months after the letters were sent. Analysis of Medicaid prescription claims indicated that 190 physicians had concurrently prescribed either an H2A or omeprazole with sucralfate for 222 patients. Ninety-seven physicians (from 117 identified patient profiles) were selected to receive an intervention letter with their patient's profile or profiles, a response form, and a stamped envelope addressed to the Texas Department of Human Services. A 67.5% response rate was obtained. Of these responses, 49.4% agreed with the letter and 29.1% disagreed with the letter. The remaining indicated responses such as "not my patient," they were no longer seeing the patient, or that they did not prescribe the medication in question. (ABSTRACT TRUNCATED AT 250 WORDS)