Abstract
Objective: assess the overdose mortality of buprenorphine, fentanyl, hydromorphone, morphine, oxycodone, tapentadol and tramadol in Australia and the morbidity and abuse rates in Western Australia.
Design: Retrospective observational study.
Setting: Australian and/or Western Australian data from the following sources; National Coronial Information System (NCIS), Western Australian Poisons Information Centre (WAPIC), Western Australian Mental Health Commission (WAMHC).
Main outcome measures: Overdose mortality (deaths attributed to opioid toxicity by the coroner), morbidity (calls to WAPIC regarding moderate to severe opioid toxicity) and abuse (number of new opioid abuse WAMHC cases and calls to WAPIC where the opioid toxicity was related to abuse) of prescription opioids, per 100,000 grams oral morphine equivalent dispensed.
Results: The overall risk of overdose mortality per prescription opioid dispensed increased by 7% over the study period. The risk of mortality, with morphine as the reference opioid, in order from highest to lowest mortality is; oxycodone 69% lower; tramadol 78%; fentanyl 84%; buprenorphine 87%; hydromorphone 91%; and tapentadol at 96% lower. Analysis of morbidity data found a significant 17% decline in the rate of cases detected for buprenorphine and a significant 11% increase in cases for oxycodone. Abuse data was insufficient to achieve statistical significance.
Conclusions: The rates of overdose mortality, morbidity and abuse differ according to the opioid dispensed even once availability and opioid strength is accounted for. These differences may be due to the inherent difference in the pharmacokinetics of each opioid and their unique effect upon the individual.