The study aims to examine the medical and non-medical use of over-the-counter (OTC) codeine combination drugs in a sample of people who inject drugs; and to examine risk factors associated with exceeding the recommended dose of OTC codeine, including the experience of pain.

This study analysed annual survey data from a convenience sample of people who inject drugs in Australia who are interviewed for the Illicit Drug Reporting System. People who have injected drugs (n = 902) on at least a monthly basis in the preceding six months across Australia were interviewed. Participants were asked about their use of OTC codeine and their experience of pain.

One third (35%) of participants had used OTC codeine in the preceding six months and 52% (95% confidence interval 48.7-55.3) of this group had exceeded the recommended dose on their last occasion of use. This clearly places them at increased risk of harms associated with toxicity from the accompanying analgesic found in combination codeine products. Multivariate analyses demonstrated that those exceeding the recommended codeine dose of OTC codeine were more likely to be experiencing moderate to very severe pain.

There is a need to evaluate the approach to pain management in this population. Greater pharmacist involvement, real-time monitoring of sales, the development of screening tools to identify those at risk of harm and further education of primary care practitioners could be beneficial in reducing the risk of harm associated with these medications for all users of OTC codeine, including people who inject drugs.