Australians have quadrupled their use of painkillers such as codeine and morphine for cancer and other chronic illnesses over a decade, a study says.
Use of opioid painkillers, including oxycodone, rose from 3287 doses per day per million to 13,440 doses per day per million.
This came amid international growth in opioid painkiller use, which doubled worldwide in that time, the Lancet study said on Wednesday. High-income western countries, including Australia, the United States and New Zealand, which made up 95 per cent of global opioid use, had largely driven the rise between 2001 and 2013.
It said that higher usage in developed countries could be due to increased pain management for cancer in ageing populations and for other chronic illnesses.
It comes as the national drug regulator, the Therapeutic Goods Administration, faces great opposition to its interim decision to stop codeine products, including common painkillers like Panadeine and Nurofen Plus from being available over the counter, to prevent people from misusing and growing dependent on them.
The TGA delayed its final ruling on this until next June after it received an "unusually large" number of submissions, mostly opposed to the proposed change.
A co-author of the study, Professor Richard Mattick at the UNSW's National Drug and Alcohol Research Centre, said that removing codeine products could make it harder for older and lower-income patients to access the medication they needed but said there was also a risk of harm associated with them. He said the TGA was best placed to make this decision.
By contrast, the study found that there was little change in the use of opioids in most of the world, which "shows a continuing absence of provision of these essential medicines".
This was despite the fact that low-income developing regions such as Africa, Eastern Europe and Asia, had a similarly high need for such painkillers as high-income countries, because chronic illnesses like cancer and AIDS tended to be diagnosed later there.
Professor Mattick said there were a number of barriers to access to painkillers in developing countries, including medical professionals' lack of training, a fear of dependence and restricted financial resources.
"Having cash in a developed society and infrastructure generally in health regulations through doctors is important," he said.
The study analysed the annual use of opioids and prevalence of disorders that needed them in 214 countries, based on data from the International Narcotics Control Board.A spokesman for the TGA said the group would review the study as part of its consideration of how codeine should be scheduled.