(257) The risk of fatal opioid overdose associated with the concurrent use of opioid analgesics and psychotropic medicines: a retrospective population-based cohort study
Scientia Associate Professor UNSW Sydney Randwick, Australia
Background: Psychotropic medicines and opioid analgesics are often concurrently prescribed, despite carrying an increased risk of adverse events, including fatal overdose. Previous studies examining the risk of fatal overdose from the concurrent use of opioids and psychotropic medicines have focused on selected medicines (e.g. benzodiazepines), and other high-risk medicines have not been well examined.
Objectives: To examine the risk of fatal opioid overdose associated with the concurrent use of opioid analgesics and psychotropic medicines, including the risk of individual medicine classes, and the additive risk associated with use of multiple psychotropic medicines.
Methods: A retrospective population-based cohort study (POPPY II) of adult (≥18 years) residents in New South Wales, Australia, who initiated prescribed opioids subsidised through the national Pharmaceutical Benefits Scheme between 1st July 2003 and 31st December 2018. Data were linked to six other datasets to provide information on socio-demographic and clinical characteristics, health service use, and adverse outcomes. Cox proportional hazards models were used to assess the association between time-dependent medicines exposure (opioid use only vs concurrent use with psychotropic medicines) and the risk of fatal opioid overdose.
Results: Of the 2,966,785 individuals in the cohort, there were 2,184 fatal opioid overdose deaths. Over one-third of the cohort (38.6%) used a psychotropic medicine concurrently with an opioid analgesic, most frequently antidepressants (24.5%) and benzodiazepines (19.8%). Compared to exposure with opioid analgesics only, the risk of fatal opioid overdose was highest among those using benzodiazepines concurrently (Adjusted Hazard Ratio (HR) 3.84, 95% Confidence Interval (CI) 2.54-5.79, followed by gabapentinoids (HR 3.22, 95% CI 2.0- 5.16). The risk of fatal overdose also increased as the number of concurrent psychotropic medicines used increased: HR 3.90, 95% CI 3.17-4.80 for 1 psychotropic medicine; HR 8.86, 95% CI 7.16-10.96 for 2 psychotropic medicines; and HR 19.55, 95% CI 15.55-24.58 for ≥3 psychotropic medicines.
Conclusions: The risk of fatal opioid overdose is elevated among people using opioid analgesics and psychotropic medicines concurrently, and varies by medicine class, and the number of medicines used. Given the frequency of use of these high-risk medicine combinations in practice, greater efforts are needed to improve the quality use of these medicines to reduce potential overdose risk.
