Health Canada advisory impact on the prevalence and trends of oral codeine use in the Pediatric Canadian population: A comparative study across provinces

Background: Since 2008, Health Canada (HC) issued several advisories indicating that oral medications containing codeine should not be given to nursing women and children/adolescents < 18 years of age. At present, no studies have assessed the impact of these advisories.

Objectives: We aimed to estimate the annual rates/trends of codeine use among the Canadian pediatric population, and the impact of federal advisories.

Methods: Setting: This multi-province, population-based cohort study analyzed data from all children/adolescents from five Canadian provinces (Alberta, Saskatchewan, Manitoba, Ontario, and Quebec) between 1996 and 2021. We performed analyses in each provincial cohort using a common protocol. All children/adolescents aged 0-18 years of age were included and categorized as follows: ≤ 12 (children) or > 12 years of age (adolescents). Exposure: We defined codeine exposure by filled prescription(s) of codeine alone or in combination with other medications. Statistical analysis: We obtained age- and province-specific rates of codeine fillings by calendar year by dividing the number of children/adolescents with at least one filled codeine prescription by person-time. We assessed the impact of the two advisories using interrupted time series analysis. We obtained their Medical specialty of the prescriber as well as the indication likely associated with the codeine prescription were obtained, using the prescribers’ unique identifier.

Results: Of the 8,156,948 children/adolescents included, 51.3% were male, with 7.2 years (SD 4.1) weighted average of follow-up. The overall annual rates of codeine use per 1,000 varied between provinces from 3.0 (Quebec) to 10.1 (Manitoba) among children, and from 5.5 to 51.3 among adolescents. Of the 974,888 codeine prescriptions over the study period, 265,181 (27.2%) were dispensed to children. After the 2013 HC advisory, exposure decreased in all provinces (adjusted level change from -0.6% to -18.4%) among children. The level change observed among adolescents after 2016 advisory varied between -2.1% to -17.9%. Codeine prescriptions were most frequently written by general practitioners (41.5%), and 32.8% mainly for diseases of the respiratory system.

Conclusions: Although codeine prescription fillings are widely used in the pediatrics population, annual rates decreased over time in all provinces; after the 2013 HC advisory among children and after 2016 HC advisory among adolescents. Although reassuring, more knowledge translation needs to be done to ensure that children/adolescents are the least exposed.