Switching the painkiller codeine to a prescription-only medicine in 2018 led to a 37 per cent overall drop in its consumption across Australia, according to new findings from wastewater sampling published in the journal Addiction.
The samples, taken from 49 wastewater treatment plants, which cover catchment areas for 10.6 million Australians, show the dramatic effect of withdrawing the country’s most misused legal opioid from pharmacy counters, cutting dependency, and potentially saving lives.
Scientists from the University of South Australia and University of Queensland compared wastewater samples taken between 2016 and 2019, 18 months before and after codeine was rescheduled and low-dose formulations removed from over-the-counter (OTC).
Codeine concentrations were converted to per capita consumption estimates, revealing an immediate decrease of 37 per cent nationally after the rescheduling and between 24 per cent and 51 per cent in all states and territories.
UniSA scientist Associate Professor Cobus Gerber says the samples – representing 45 per cent of the country’s population – demonstrate the effectiveness of the Federal Government’s decision to take tough measures on the popular painkiller.
Opioids are among the most widely used analgesic medicines globally, with more than 61 million people using them in 2018.
Their misuse is responsible for two thirds of all drug-related deaths, due to abuse and dependence.
Codeine has been the most widely used legal opioid in Australia, with its per capita use steadily increasing. 2013 data showed Australia took more codeine as a country than the United States, despite having roughly seven per cent of the population.
The study is the first to evaluate a national drug policy change via wastewater sampling.
