Changes in doxylamine-pyridoxine dispensation in Ontario following media attention: Time-series analysis.

Objective: To understand the possible association between media coverage and changes in the dispensation of doxylamine-pyridoxine in Canada.

Design: Cross-sectional time-series analysis using data from the IQVIA CompuScript database.

Setting: Ten Canadian provinces.

Participants: Family physicians, general practitioners, and obstetrician-gynecologists.

Main Outcome Measures: Data on the estimated total volume of doxylamine-pyridoxine prescriptions dispensed by retail pharmacists in Ontario and across Canada between July 2016 and May 2022 were used for a time-series analysis. Birth data obtained from Statistics Canada were used to adjust for pregnancy rates. Finally, the possible impact of media coverage in January 2018 on doxylamine-pyridoxine use was assessed with interventional autoregressive integrated moving average modelling, and dispensation rates of doxylamine-pyridoxine were reported overall and by prescriber specialty.

Results: Doxylamine-pyridoxine dispensation decreased by 1.2% (=.015) overall in Ontario but did not change significantly (=.064) across the rest of Canada. Out of 619,720 total doxylamine-pyridoxine prescriptions dispensed, 391,722 (63.2%) prescriptions were written by family physicians or general practitioners in Ontario, and there was a decline of 2.4% (=.010) in the dispensation of doxylamine-pyridoxine based on prescriptions written by this group that lasted for 6 months before returning to previous dispensation rates. There was no significant change in the dispensation of doxylamine-pyridoxine based on prescriptions written by obstetrician-gynecologists (decline of 0.5%, =.235) in Ontario.

Conclusion: Despite nationwide media attention questioning the efficacy of doxylamine-pyridoxine in early 2018, trends in dispensation rates of doxylamine-pyridoxine were only modestly affected and only in Ontario. Within Ontario, a small but significant reduction in doxylamine-pyridoxine dispensations was noted based on prescriptions from family physicians or general practitioners but not based on those written by obstetrician-gynecologists. Factors associated with the ongoing use of doxylamine-pyridoxine despite evidence of lack of benefit require further research.