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.