Codeine use down by 37% since up-scheduling

New research suggests shifting codeine to a prescription-only medicine has had a sizeable impact on harm reduction, opioid dependency and related deaths across Australia.
 
Wastewater analyses of samples collected between August 2016–19 show that average per-capita consumption of codeine decreased by 37% nationally, immediately after it was up-scheduled in February 2018.
 
Additionally, codeine use dropped substantially across all jurisdictions: between 24–51%.
 
The study, conducted by researchers from the University of South Australia (UniSA) and University of Queensland (UQ), analysed 3703 wastewater samples from 48 treatment plants across the country, representing 10.6 million people – or 45% of Australia’s population.
 
The results also appear to support previous studies, that showed a 50% decrease in overdoses and sales of the opioid soon after codeine was up-scheduled to a Schedule 4 medicine.

RACGP addiction medicine specialist Dr Paul Grinzi told newsGP the wastewater study’s results ‘align well with what we already know’ regarding the effects of Australia’s codeine up-scheduling.
 
‘Codeine use dropped significantly and this drop has been sustained,’ he said.
 
‘It is interesting for GPs to also note that this policy change did not lead to previously feared unintended negative consequences, such as adverse impacts on pain, measures of worsening mental health distress or an increase in the use of alternate opioid medications.’
 
The National Wastewater Drug Monitoring Program commenced in August 2016, and while the study authors note that wastewater monitoring is unable to provide ‘conclusive reasons for consumer behaviour’, it does show the effectiveness of interventions such as codeine rescheduling.
 
‘Less availability not only means less chance for codeine to be misused, but also changing the perception of codeine being a harmless drug,’ lead UQ author Dr Ben Tscharke said.
 
‘Codeine is typically prescribed for short-term, acute pain management, but there was anecdotal evidence that many people used it as a first-line treatment and for extended periods, without consulting a doctor.
 
‘Making it prescription-only sends a clear message about how dangerous it is.’
 
Prior to codeine becoming a Schedule 4 prescription-only medicine, its associated harms were clear.
 
The Therapeutic Goods Administration estimates that before 2018, over-the-counter sales of the drug were responsible for more than 100 deaths each year, with codeine deaths more than doubling from 2000–09 in Australia.
 
In 2016–17, codeine was the second most commonly prescribed opioid after oxycodone, at 3.7 million prescriptions to 1.7 million people, and of people who reported non-medical use of analgesics and pharmaceutical opioids, 75% had used over-the-counter codeine products.
 
Further, codeine was among the most commonly mentioned ‘naturally derived opioids’ in opioid-related deaths in 2016, which were attributed to 49% of opioid deaths.
 
The UQ/UniSA study – the first to evaluate a national drug policy change via wastewater sampling – found that regional areas had a smaller margin of decreased codeine use than cities.
 
South Australia and Tasmania had the smallest decreases, with an average of 25%, while the Northern Territory had the largest decrease of 51%.
 
Prior to the drug’s up-scheduling, rates of codeine use were approximately 25% higher in regional areas, and highest in the most remote areas.
 
Locations with reduced pharmacy access had a decrease in use of 51% compared to 37% observed for those with greater access to pharmacies.
 
Data for the study were collected using Pharmacy Access/Remoteness Index of Australia (PhARIA) codes by measuring the accessibility of pharmacies across each geographic location.
 
When these codes were applied to assess ‘general access to first-line services across the sites for a more granular definition’, the authors note the ‘greatest decrease in codeine consumption was observed in areas with the least access to pharmacies’, most of which were regional.
 
‘The PhARIA describes general access to a key first-line medical service, suggesting that a greater proportion of codeine use in the most remote areas may have been obtained over-the-counter, because [these] sales ceased post-rescheduling,’ they wrote.

The study also found that national sales of codeine during 2016–19 did not entirely match wastewater estimates, showing a combined 50% decrease in total packs of codeine sold, with the researchers saying that ‘stockpiling’ contributed to the difference in delays to consumption.

Overall, similar reductions were reported for poison call centres, where opioid poisonings halved after the up-scheduling of codeine.
 
Dr Grinzi believes the study further supports GPs’ role in monitoring opioid use and providing safe and effective pain management.
 
‘GPs are well aware that ongoing opioids are not recommended as part of the management of chronic pain,’ he said.
 
‘This information provides further reassurance that we can continue to assist our patients to move away from opioid therapy – including codeine – for chronic pain treatment.’ 

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