Twenty-five years of prescription opioid use in Australia: a whole-of-population analysis using pharmaceutical claims

Aim: The aim of this paper is to investigate 25-year trends in community use of prescribed opioid analgesics in Australia, and to map these trends against major changes to opioid registration and subsidy.

Methods: We obtained dispensing data from 1990 to 2014 from two sources: dispensing claims processed under Australia's national drug subsidy programme, the Pharmaceutical Benefits Scheme, including under co-payment records from 2012; and estimates of non-subsidized medicine use from a survey of Australian pharmacies (until 2011). Utilization was expressed in defined daily doses (DDD)/1000 population/day.

Results: Opioid dispensing increased almost four-fold between 1990 and 2014, from 4.6 to 17.4 DDD/1000 pop/day. In 1990, weak, short-acting or orally administered opioids accounted for over 90% of utilization. Use of long-acting opioids increased over 17-fold between 1990 and 2000, due primarily to the subsidy of long-acting morphine and increased use of methadone for pain management. Between 2000 and 2011, oxycodone, fentanyl, buprenorphine, tramadol and hydromorphone use increased markedly. Use of strong opioids, long-acting and transdermal preparations also increased, largely following the subsidy of various opioids for noncancer pain. In 2011, the most dispensed opioids were codeine (41.1% of total opioid use), oxycodone (19.7%) and tramadol (16.1%); long-acting formulations comprised approximately half, and strong opioids 40%, of opioid dispensing.

Conclusions: Opioid utilization in Australia is increasing, although these figures remain below levels reported in the US and Canada. The increased use of opioids was largely driven by the subsidy of long-acting formulations and opioids for the treatment of noncancer pain.