The impact of codeine re-scheduling on misuse: a retrospective review of calls to Australia's largest poisons centre

Abstract

Background and aims: Codeine is the most commonly used opioid in the world, and is available over the counter (OTC) in many countries, including Australia. Several countries are reconsidering codeine's OTC status due to concerns over addiction and misuse, with serious morbidity and mortality being reported. Australia's Therapeutic Goods Administration restricted codeine containing analgesics to 'Pharmacist Only' in 2010, and has recently been considering further up-scheduling to make codeine 'Prescription Only'. This paper estimated Australian trends of codeine misuse over the past 12 years, and examined whether trends changed following previous rescheduling efforts in 2010.

Design: A retrospective review of calls regarding codeine misuse made to the New South Wales Poisons Information Centre (NSWPIC, Australia's largest poisons centre), 2004-15. Joinpoint software was used to quantify the average annual change in calls, and whether there was a significant change in trend at any time, including following rescheduling.

Setting: Australia.

Participants: Four hundred patients about whom a call was made to the NSWPIC.

Measures: Calls per year, patient age, gender, tablets taken per day, formulation used, symptom disposition.

Findings: The NSWPIC database contained 400 cases of codeine combination analgesic misuse from 2004 to 2015. Joinpoint analysis showed that the frequency of cases increased significantly from 2004 to 2015, with an average annual percentage change (AAPC) of 19.5% [95% confidence interval (CI) = 13.8-25.5% P < 0.0001] for paracetamol/codeine and 17.9% (95% CI = 7.9-28.9%, P < 0.01) for ibuprofen/codeine. No significant change in trend was seen at any time, including following 2010 rescheduling. The median age of patients was 34 and 27 years for paracetamol/codeine and ibuprofen/codeine cases, respectively. Gender distribution was approximately equal. Clinical features reported were consistent with codeine, paracetamol and ibuprofen toxicity.

Conclusions: Misuse of codeine combination products appears to be increasing in Australia. Limited rescheduling in 2010 failed to curb this increase.

Keywords: Codeine; dependence; misuse; opioids; over-the-counter; poisons centres; policy.