Trends and changes in prescription opioid analgesic dispensing in Canada 2005–2012: an update with a focus on recent interventions

BACKGROUND Prescription opioid analgesic (POA) utilization has steeply increased globally, yet is far higher in established market economies than elsewhere. Canada features the world's second-highest POA consumption rates. Following increases in POA-related harm, several POA control interventions have been implemented since 2010. METHODS We examined trends and patterns in POA dispensing in Canada by province for 2005-2012, including a focus on the potential effects of interventions. Data on annual dispensing of individual POA formulations--categorized into 'weak opioids' and 'strong opioids'--from a representative sub-sample of 5,700 retail pharmacies across Canada (from IMS Brogan's Compuscript) were converted into Defined Daily Doses (DDD), and examined intra- and inter-provincially as well as for Canada (total). RESULTS Total POA dispensing--driven by strong opioids--increased across Canada until 2011; four provinces indicated decreases in strong opioid dispensing; seven provinces indicated decreases specifically in oxycodone dispensing, 2011-2012. The dispensing ratio weak/strong opioids decreased substantively. Major inter-provincial differences in POA dispensing levels and qualitative patterns of POA formulations dispensed persisted. Previous increasing trends in POA dispensing were reversed in select provinces 2011-2012, coinciding with POA-related interventions. CONCLUSIONS Further examinations regarding the sustained nature, drivers and consequences of the recent trend changes in POA dispensing--including possible 'substitution effects' for oxycodone reductions--are needed.