Postdated versus usual delayed antibiotic prescriptions in primary care: Reduction in antibiotic use for acute respiratory infections?

OBJECTIVE To determine whether postdating delayed antibiotic prescriptions results in a further decrease (over usual delayed prescriptions) in antibiotic use. DESIGN Randomized controlled trial. SETTING A small rural town in Newfoundland and Labrador. PARTICIPANTS A total of 149 consecutive adult primary care patients who presented with acute upper respiratory tract infections. INTERVENTION Delayed prescriptions for patients who might require antibiotics were randomly dated either the day of the office visit (ie, the usual group) or 2 days later (ie, the postdated group). MAIN OUTCOME MEASURES Whether or not the prescriptions were filled and the time it took for the patients to fill the prescriptions were noted by the 4 local pharmacies and relayed to the investigators. RESULTS In total, 149 delayed antibiotic prescriptions were written, 1 per patient. Of the 74 usual delayed prescriptions given out, 32 (43.2%) were filled; of the 75 postdated delayed prescriptions given out, 33 (44.0%) were filled. Sixteen patients from each group filled their delayed prescriptions earlier than the recommended 48 hours. Statistical analyses-χ² tests to compare the rates of antibiotic use between the 2 groups and t tests to compare the mean time to fill the prescription between the 2 groups-indicated that these results were not significant (P > .05). CONCLUSION Although delayed prescriptions reduce the rate of antibiotic use, postdating the delayed prescription does not seem to lead to further reduction in use.