Opioid painkillers, even at high doses, provide minimal benefit for people with low back pain, new research suggests.
"People have the mistaken belief that opioids are strong pain killers," says Professor Chris Maher from The George Institute.
"When you look closely at the evidence from the low back pain trials, a completely different picture emerges."
The findings of the systematic review, by the institute and the University of Sydney, are published in JAMA Internal Medicine.
Low back pain is a common health problem and the leading cause of disability in the world.
In Australia, 40 per cent of patients who see a GP for low back pain are prescribed an opioid painkiller, say the researchers.
As well as concluding that the drugs provide little clinical benefit, the study found that half of trial participants withdrew because of adverse effects to the medicine or lack of effect.
"For people who can tolerate the medicine, taking an opioid analgesic such as oxycodone will reduce pain, but the effect is likely to be small," Prof Maher said.
"This result reinforces the recent US Centers for Disease Control and Prevention (CDC) recommendation that if opioids are used, they should be combined with non-drug options such as physiotherapy or non-opioid painkillers, as appropriate."
More research was needed to find out the effects of long term use of opioid analgesics, said co-author Prof Andrew McLachlan, from the University of Sydney.