Non-medical use of pharmaceutical opioids with and without other illicit substance use: Trends from two repeated nationally representative Australian surveys.

A comparison of cross-sectional data from two time-points showed that the prevalence of NMUPO use among people who used NMUPO exclusively was lower post-up-scheduling of codeine in Australia. However, NMUPO use did not reduce among people who used both NMUPO and other illicit drugs. Public health interventions are needed to reduce opioid-related harm in those who also used other illicit drugs.