Trends in transdermal fentanyl utilisation and fatal fentanyl overdose across Australia (2003-2015)

Introduction Fentanyl-related overdose is an ongoing concern among countries with high prescription opioid utilisation. This study examines trends in transdermal fentanyl utilisation and fatal fentanyl overdose across Australia between 2003 and 2015, overall, and by age/sex. Methods This was a retrospective nationwide study of prescription dispensings and coronial records. Transdermal fentanyl utilisation was examined using Pharmaceutical Benefits Scheme dispensing records. Details of fatal fentanyl overdoses were extracted from the National Coronial Information System. Results Transdermal fentanyl utilisation increased 5.1-fold between 2003 and 2015, from 0.28 to 1.39 mg/1000 population/day and was consistently higher among females and adults aged >= 85 years. The utilisation of higher strength patches (75 and 100 mcg/h) was more common among males aged 25-44 years. A total of 291 fatal fentanyl overdoses were recorded, increasing from no recorded deaths in 2003 to 2.23 deaths/1 000 000 population in 2015. Rates were higher among males (increasing from 0 to 3.72 deaths/1 000 000 population) and for adults aged 25-44 years (increasing from 0 to 5.34 deaths/1 000 000 population). The number of deaths/kg fentanyl dispensed was highest among males aged <25 years (45.45, 95% confidence interval 21.80-83.59). Most deaths (70.1%) involved the intravenous administration of fentanyl from transdermal patches. Discussion and Conclusions Rates of transdermal fentanyl utilisation and fatal fentanyl overdose across Australia increased between 2003 and 2015. Although transdermal fentanyl utilisation was consistently greater among females and older adults, rates of fatal fentanyl overdose were highest among younger males. Interventions to reduce extramedical use among this high-risk population group are necessary to minimise fentanyl-related harms.