Changes in opioid prescriptions following codeine becoming a prescription only medicine in Australia
In Australia in February 2018, codeine became a prescription medication. This decision was implemented after almost 3 years of consideration, following reports of rising harms including dependence and mortality from over-the-counter codeine. It is critical to evaluate the outcomes of regulatory decisions intended to address extramedical opioid use. As such, this study aimed to examine the impact of codeine rescheduling on broader opioid supply patterns in Australia.
We examined national prescription opioid supply data for seven commonly used opioids from January 2016 to November 2018, using data from the Australian Pharmaceutical Benefits Scheme (PBS). We used segmented regression analysis of the interrupted time series to examine trends in opioid supply by individual opioids, and as an aggregated measure of total opioid supply. To examine aggregated opioid supply, quantities of individual opioids supplied were converted into an Oral Morphine Equivalents and summed across different products and opioid types. Use of three high volume prescription medicines (amoxicillin, atorvastatin and pantoprazole) were used for comparison where unexpected temporal patterns were observed.
These preliminary analyses indicate that the rescheduling of codeine has not led to a significant increase in prescription of codeine, or an increase in any other opioid, or the total amount of opioids supplied through the Australian PBS.
Longer-term follow-up and analysis of additional indicator data sources is required to fully understand the outcomes of regulatory changes, though initial analysis suggests that removal of codeine for sale as an over-the-counter medicine has not resulted in an increase in prescribed codeine, or an increase in the prescription other opioids or total opioid supply. As data become available, further analyses should consider other indicators of opioid consumption, indicators of opioid-related harm and individual outcomes for those experiencing codeine dependence at the time of the rescheduling to more completely evaluate the outcome of codeine rescheduling.