The effect of an Rx-to-OTC switch on medication prescribing patterns and utilization of physician services -: The case of H2-receptor antagonists

BACKGROUND. Prescription medications are being switched to over-the-counter (OTC) status with increasing frequency. information is limited regarding the impact of OTC availability on the use of prescription forms of those products and on the utilization of health care services. OBJECTIVES. TO determine the impact of OTC availability of H-2-receptor antagonists on medication prescribing patterns and utilization of physician services among a population of chronic users of those agents. DESIGN. A retrospective study was conducted to evaluate changes in the number of prescriptions filled for H-2-receptor antagonists and other gastrointestinal. agents (proton pump inhibitors, gastric motility agents, and sucralfate), and ambulatory medical encounters with physicians during a one-year period before (July I, 1994-June 30, 1995) and after OTC availability of H-2-receptor antagonists (July 1, 1995-June 30, 1996). Changes in the prescription drug costs for gastrointestinal agents were also estimated. SUBJECTS. Members of the Fallen Community Health Plan, a mixed-model HMO located in Central and Eastern Massachusetts (July 1, 1994-June 30, 1996) who were dispensed at least one H-2-receptor antagonist during each quarter for the period between July 1, 1994 through June 30, 1995. MEASURES. Mean absolute differences in the frequencies of drug dispensings and ambulatory encounters and prescription drug costs during the pre-OTC (July I, 1994-June 30, 1995) and post-OTC switch (July 1, 1995-June 30, 1996) periods were calculated. RESULTS. For the one-year period after OTC availability H-2-receptor antagonists, we estimated that the mean absolute number of prescriptions dispensed for H-2-receptor antagonists was reduced by 1.5 prescriptions (P < 0.001) and the mean number of prescriptions dispensed for all gastrointestinal agents was reduced by 1.3 prescriptions (P < 0.001) among chronic users of these agents. The number of dispensings of gastrointestinal agents was similarly reduced in the population of chronic users with a diagnosis of gastroesophageal reflux disease (GERD). OTC availability was not associated with an increase in physician visits, overall or for GERD-related conditions. CONCLUSIONS. The findings of this study suggest that the prescription-to-OTC switch of H-2-receptor antagonists reduced the number of prescriptions for those agents dispensed among a population of chronic users of those drugs in a managed care setting without increasing physician visits.