Hospital admissions for paracetamol poisoning declined following codeine re-scheduling in Australia

Codeine was restricted to prescription only in Australia in 2018. This intervention aimed to reduce harms from codeine dependance and use, including toxicity from co-formulated paracetamol. We aimed to quantify the impact of this intervention on paracetamol poisoning hospital admissions in a national hospital admissions database. We analyzed the number of paracetamol overdoses resulting in hospital admissions from the Australian Institute of Health and Welfare National Hospital Morbidity Database, January 2011 to June 2020. We used interrupted time series analysis to quantify the effect of codeine re-scheduling on the monthly number of paracetamol poisoning-related hospital admissions in Australia. We compared paracetamol poisonings with no opioid combinations, and poisonings with probable paracetamol-codeine combinations. There was an immediate and sustained decrease (level shift) in the number of paracetamol poisoning-related hospital admissions following codeine re-scheduling (RR=0.85; 95% CI 0.80–0.89). This reduction was due to the decrease in poisonings with likely paracetamol-codeine combinations (RR=0.62; 95% CI 0.57–0.67) while there was no change in other paracetamol poisonings (RR=0.91; 95% CI 0.96–1.01). Codeine re-scheduling in Australia appears to have reduced paracetamol poisoning-related hospital admissions.