Codeine and oxycodone were the most prevalent opioids related to ambulance attendances for extramedical opioid use over a six-year period, study finds
A retrospective study has analysed 9,823 opioid-related ambulance attendances across Victoria from January 2013 to September 2018.
Researchers from Monash University also examined ambulance attendances across NSW, ACT, Northern Territory, Queensland and Tasmania and found the data were broadly consistent with that of Victoria.
Extramedical use of buprenorphine, codeine, fentanyl, oxycodone, oxycodone-naloxone, morphine, pethidine, tramadol, and tapentadol were examined, with the results showing that rates and characteristics of opioid-related harm vary by opioid type.
“Not all pharmaceutical opioids are the same in terms of the number of ambulance attendances we see with them nor the characteristics that are associated with them,” explained lead author Associate Professor Suzanne Nielsen, Deputy Director of the Monash Addiction Research Centre in Melbourne.
Codeine and oxycodone had the highest rates of attendance per 100,000 Oral Morphine Equivalent mg (OME).
And while fentanyl and tapentadol had the lowest rates of attendance, fentanyl-related attendances were associated with the most severe characteristics, for example, low consciousness, most likely to be an accidental overdose, most likely to have naloxone administered, more likely to include men and less likely to be transported to hospital.
However codeine had the highest rates of harm, the researchers found.
The attendance rate for codeine – the lowest-potency opioid examined – was more than 50 times that of the lowest rate observed with tapentadol.
Codeine-related attendances were more likely to involve younger females as well as suicidal thoughts and behaviours, and less likely to represent accidental overdoses.
Codeine was available in Australia without a prescription for the majority of the study period.
However sales data showed supply was approximately evenly split between the OTC and prescribed codeine, with minimal supply as a restricted single-ingredient product.
“It is possible that ease of access and the compounded ingredients (e.g. acetaminophen-codeine combinations) contributed to the harms observed,” the authors said.
“Both codeine and tramadol-related attendances, the two lesser-restricted opioids in Australia, represented largely younger females with suicidal or self-injurious intent, consistent with international evidence.”
“We did see those codeine attendances starting to tail off in terms of the raw numbers towards the end of the study, which coincides with when it was rescheduled,” A/Prof Nielsen told AJP.
“But still being one of the most available opioids, we did see a high number of attendances that were associated with codeine.”
Another interesting finding was the contrast between oxycodone as a single ingredient compared to oxycodone-naloxone, she said.
The data showed three times as many presentations for every kilogram of oxycodone supplied as a single ingredient product, compared to the equivalent amount supplied as an oxycodone-naloxone product.
Attendances were rare for buprenorphine (transdermal) and pethidine. Rates of morphine attendances were noticeably higher in states other than Victoria.
“Self-harm and suicidal thoughts and behaviours were quite prevalent amongst people who had attendances associated with extramedical use of pharmaceutical opioids,” A/Prof Nielsen said.
“It goes to highlight just how complex responding to extramedical pharmaceutical opioid use is… We’re not likely to have a ‘quick fix’ when we see these patients with such complex profiles – often with chronic pain, quite a lot of distress and reporting these kinds of suicidal thoughts and behaviours.
“So I think while we very strongly support naloxone for overdose prevention—it’s critical—I think we also need to think about other strategies. There’s work already looking at how community pharmacy can better respond to people who present with suicidal thoughts and behaviours and I think that’s a really critical area to pursue.
“What this research might add is being mindful of checking in with patients around how they’re coping with their pain and their other symptoms. Where patients might be struggling to cope, opioids alone are probably insufficient and they most likely need support to develop other strategies and maybe referral back to some of those additional support multimodal pain management services that we know have a strong evidence base,” she said.
A/Prof Nielsen also highlighted the importance of messages about safe storage of medicines, having them locked away and out of reach of children and teenagers.
“We know from research that having medicines available when people are feeling impulsive or suicidal can increase the risk and actually, we do tend to see when means are reduced that people don’t substitute and that often that will reduce their risk and those impulses will pass.
“There have been a number of studies that have looked at that and it is an important strategy to reduce availability of means, particularly with pharmaceuticals being so commonly implicated in self-poisonings.”
See the full study here (open access)