Australians are being urged not to use highly addictive benzodiazepines, or benzos, such as Valium to relieve back pain.
There is no evidence that the minor tranquilisers relieve low back muscle spasms and should be avoided, says pain medicine physician Dr Mick Vagg.
"There's a belief that diazepam (Valium), which is probably the most commonly used one, is helpful as a way of relieving muscle spasm in acute back pain but in fact there's basically no evidence to support its use in someone with acute back pain," Dr Vagg told AAP.
Dr Vagg says the one and only study conducted on their use in the last 40 years shows their use "wasn't worth it".
With nearly 80 per cent of Australians to suffer some form of low back pain, The Faculty of Pain Medicine of the Australian and New Zealand College of Anaesthetists have joined forces with Choosing Wisely Australia to warn against their use.
"The thing with these drugs is that they are very hard to get off if you stay on them for more than a few weeks because they tend to produce quite severe withdrawals if they are not slowly weaned," said Dr Vagg.
This is a particular problem for those with chronic back pain, he noted.
"In our pain management practice most of the patients that are on benzodiazepines, which would be perhaps 40 per cent of our patients, got started on it as a way of trying to improve muscle spasms. Some of them got on it for anxiety but most of them got started on it when it was introduced to treat their back spasms."
Other side effects associated with long-term use of benzodiazepines include increased risk of falls, cognitive decline, accidents with driving and in combination with opioids increased risk of sudden death.
New advice has also been issued on treating chronic non-cancer pain with opioids.
"Managing chronic pain is complex, but there is little evidence to support the use of opioids as the first or only treatment option," Dr Vagg said.