Comparing rates and characteristics of harms across different pharmaceutical opioids: an examination of Australian ambulance attendances 2013-2018.

Background. Similar to other high-income countries, Australian opioid-related mortality has almost doubled in the past decade, and the majority of the deaths are pharmaceutical opioid-related. Despite common extramedical use, few studies examine the relative harms associated with different pharmaceutical opioids.

Aims. This study aimed to describe rates and characteristics of ambulance attendances related to nine commonly prescribed pharmaceutical opioids: buprenorphine, codeine, fentanyl, oxycodone, oxycodone-naloxone, morphine, pethidine, tramadol, and tapentadol.

Method: Trained research assistants coded clinical records of ambulance attendances from January 2013 to September 2018. Cases were included where recent extramedical (i.e. over- or inappropriate) use of a pharmaceutical opioid significantly contributed to the reason for the ambulance attendance.

We examined supply-adjusted rates of attendances using Poisson regression and used multinomial logistic regression to compare severity and other characteristics of attendances associated with different pharmaceutical opioids in Victoria (Australia’s second largest state), and compared these to the other jurisdictions of Australia.

Results. We identified 14 161 ambulance attendances relating to extramedical use of pharmaceutical-opioids. In Victoria, the highest rates of attendance (per 100 000 mg OME) were for codeine (0.273/100 000) and oxycodone (0.113/100 000). The lowest rates were for fentanyl (0.019/100 000) and tapentadol (0.005/100 000). Rates of oxycodone-naloxone-related attendances (0.031/100 000) were lower than for oxycodone as a single ingredient (0.113/100 000).

Fentanyl-related attendances were the most severe, most likely to be an accidental overdose and have naloxone administered, and least likely to be transferred to hospital. In contrast, codeine-related attendances were more likely to involve co-morbid suicidal thoughts or behaviours, involve younger females and require transport to hospital for further care.

Despite significant changes in the volume of supply for different opioids over the study period, rates of supply-adjusted harm remain relatively stable. Data from states outside Victoria were broadly consistent.

Discussion. This study represents one of the most detailed population level examinations of pharmaceutical opioid-related harm in Australia. Distinct patterns of harms were observed for different opioids. These highlight the need to consider factors such as the formulation, to develop nuanced responses to reduce pharmaceutical opioid-related harm, particularly as newer formulations are introduced. Furthermore, policy attention has largely focused on accidental overdose, with less consideration of interventions aimed at intentional harm. Policy makers may consider the role of regulation in addressing harms from pharmaceutical self-poisoning.