Codeine use and harms in Australia: evaluating the effects of re-scheduling
Cairns R., Schaffer AL., Brown JA., Pearson SA., Buckley NA.
Background and aims: Globally, codeine is the most-used opioid. In December 2016, Australia announced that low-strength codeine (≤ 15 mg) would be re-scheduled and no longer available for purchase over-the-counter; this was implemented in February 2018. We aimed to evaluate the effect of this scheduling change on codeine misuse and use and misuse of other opioids. Design and setting: Interrupted time–series analysis of monthly opioid exposure calls to New South Wales Poisons Information Centre (NSWPIC, captures 50% of Australia's poisoning calls), January 2015– January 2019 and monthly national codeine sales, March 2015–March 2019. We incorporated a washout period (January 2017 – January 2018) between the announcement and implementation, when prescriber/consumer behaviour may have been influenced. Participants: Intentional opioid overdoses resulting in a call to NSWPIC. Measurements: We used linear segmented regression to identify abrupt changes in level and slope of fitted lines. Codeine poisonings and sales were stratified into high strength (> 15 mg per dose unit) and low strength (≤ 15 mg). Only low-strength formulations were re-scheduled. Findings: We observed an abrupt −50.8 percentage [95% confidence interval (CI) = −79.0 to −22.6%] level change in monthly codeine-related poisonings and no change in slope in the 12 months after February 2018. There was no increase in calls to the NSWPIC for high-strength products, level change: –37.2% (95% CI = −82.3 to 8%) or non-codeine opioids, level change: –4.4% (95% CI = −33.3 to 24.4%). Overall, the re-scheduling resulted in a level change in opioid calls of −35.8% calls/month (95% CI = −51.2 to −20.4%). Low-strength codeine sales decreased by 87.3% (95% CI = −88.5 to −85.9%), with no increase in high-strength codeine sales in the 14 months following re-scheduling, −4.0% (95% CI = −19.6 to 14.6%). Conclusions: Codeine re-scheduling in Australia appears to have reduced codeine misuse and sales.