The move to prescription-only codeine in Australia has seen a 50 percent reduction in the monthly rate of codeine-related poisoning calls and halved codeine sales, finds new research led by the University of Sydney.
The study, published today in Addiction, is the first peer-reviewed research to examine the short-term implications of the removal of over-the-counter sales of low-strength codeine in February 2018.
Researchers from the University of Sydney, New South Wales Poisons Information Centre (NSWPIC) and the University of New South Wales looked at intentional poisoning and purchase behaviour by analysing call data from the NSW Poisons Information Centre and national sales data.
Lead author Dr Rose Cairns from the University of Sydney and NSW Poisons Information Centre said the data paints a positive picture of the impact of the legislative changes.
We saw a massive and abrupt reduction in codeine poisonings following the 2018 move to prescription-only sales."
Dr Cairns, lecturer in Sydney Pharmacy School and Director of Research at the NSW Poisons Information Centre
"Interestingly, and despite what many predicted, we didn't see an increase in poisonings with higher-strength codeine or stronger opioids, so it really is a good news story.
"The sales data also showed a similar picture. There were big reductions in sales of low-strength codeine, with no increase in sales of higher strength codeine."
In the 12 months following the changes the researchers found:
- 50 percent reduction in the monthly rate of codeine-related poisoning calls
- 79 percent decrease in low-strength poisoning calls with no significant change in high-strength poisoning calls (only low-strength codeine products containing ? 15mg codeine per dose unit were affected by the legislative change)
- no significant increase in poisoning calls with other pharmaceutical opioids
- no significant change in the codeine dose taken in intentional poisonings.
The NSWPIC is Australia's largest poisoning information centre and captures approximately 50 percent of the nation's annual poisoning calls. It receives calls from healthcare professionals and members of the public both within and outside NSW.
In the 14 months following the changes researchers found:
- overall codeine sales halved
- low-strength codeine sales decreased by 87 percent
- there was no change in sales of higher strength preparations.
IQVIA sales data included national sales data on codeine purchases made through wholesalers and manufacturers by retail pharmacies and hospitals. IQVIA is a global company that provides pharmaceutical sales data.
Codeine use in Australia:
Codeine is an opioid drug often found in pain killer and cold and flu medication, or cough mixtures.
Prior to the legislative changes, codeine was the most commonly used opioid analgesic in Australia, with consumption exceeding that of the United States despite Australia having a population seven percent the size of the US.
The February 2018 changes followed a lengthy consultation and mean that people needing low-strength codeine must now first obtain a prescription from their GP or health care provider.
"There are serious concerns about the long-term use of codeine, both in regard to dependence issues and general health," said Dr Cairns.
"The doses of codeine previously available over-the-counter were not very effective, yet can still lead to opioid dependence and side effects. In addition, genetic differences mean there is wide variability in how people respond to codeine."
Senior author on the study and Professor of Clinical Pharmacology Nicholas Buckley from the University of Sydney said the changes belatedly bring Australia in line with most other countries in regards to codeine availability.
"Australia has had a 50 percent increase in overall poisoning deaths in the last decade. A systematic strategy to address the causes of the rise in fatal poisoning is urgently needed," said Professor Buckley.
"This study and also similar results with the recent changes to the availability of anxiety medication alprazolam demonstrate how effective simple interventions could be in tackling this epidemic."
Cairns, R. et al. (2019) Codeine use and harms in Australia: evaluating the effects of re‐scheduling. Addiction. doi.org/10.1111/add.14798.