Prescription-Duration Patterns of Outpatient Macrolide Use in Participating Community Pharmacies in Tokyo, Japan: A 24-Month Repeated Cross-Sectional Study

Background: Macrolides are classified in the Watch group of the World Health Organization Access, Watch, and Reserve (AWaRe) classification and are prescribed for both acute infections and chronic respiratory diseases. Aggregate antimicrobial use indicators do not distinguish short- from extended-duration prescribing. This study characterized outpatient macrolide prescription-duration patterns using community pharmacy dispensing data. Methods: A retrospective observational study comprising repeated cross-sectional analyses at the drug prescription-record level and a secondary patient-level longitudinal analysis was conducted using anonymized dispensing data from participating community pharmacies in Tokyo, Japan, collected between April 2023 and March 2025. Prescription durations were classified as 1–14, 15–28, 29–89, and ≥90 days. The primary outcome was a prescription duration of ≥29 days, corresponding to the Japanese dispensing-fee classification during the study period. Modified Poisson regression was used to estimate associations with extended-duration prescription records. Results: The analysis included 200,632 systemic macrolide drug prescription records from 139,293 pharmacy-specific patient keys. Overall, 13,555 records (6.8%) had durations of ≥29 days. The proportion increased from 1.6% among patients aged 0–14 years to 25.4% among those aged ≥75 years. Compared with patients aged 15–39 years, the adjusted prevalence ratios were 2.11 (95% CI, 1.73–2.57) for those aged 40–64 years, 4.30 (95% CI, 3.18–5.82) for those aged 65–74 years, and 5.45 (95% CI, 3.98–7.47) for those aged ≥75 years. Marked differences were observed among macrolide agents and formulations. Sensitivity analyses excluding exact duplicates, restricting the analysis to continuously contributing pharmacies, and using an alternative clustering specification supported the principal adult/older-age and agent-specific findings. Conclusions: Extended-duration macrolide dispensing records were more frequently observed in older age groups and specific erythromycin formulations among participating pharmacies. Prescription-duration and repeated-prescribing measures may complement conventional antimicrobial utilization indicators by identifying strata for subsequent indication-linked review; they should not be interpreted as stand-alone measures of prescribing appropriateness.