To examine trends in codeine-related mortality rates in Australia, and the clinical and toxicological characteristics of codeine-related deaths.

Analysis of prospectively collected data from the National Coronial Information System on deaths where codeine toxicity was determined to be an underlying or contributory cause of death. The study period was 2000-2013.

Population-adjusted numbers (per million persons) of (1) codeine-related deaths, classified by intent (accidental or intentional); and (2) heroin- and Schedule 8 opioid-related deaths (as a comparator).

The overall rate of codeine-related deaths increased from 3.5 per million in 2000 to 8.7 per million in 2009. Deaths attributed to accidental overdoses were more common (48.8%) than intentional deaths (34.7%), and their proportion increased during the study period. High rates of prior comorbid mental health (53.6%), substance use (36.1%) and chronic pain (35.8%) problems were recorded for these deaths. For every two Schedule 8 opioid-related deaths in 2009, there was one codeine-related death. Most codeine-related deaths (83.7%) were the result of multiple drug toxicity.

Codeine-related deaths (with and without other drug toxicity) are increasing as the consumption of codeine-based products increases. Educational messages are needed to better inform the public about the potential harms of chronic codeine use, especially in the context of polypharmacy.