Muscle relaxants are largely ineffective and potentially unsafe when treating low back pain but are still being widely prescribed, Australian researchers have found.
Researchers from the Neuroscience Research Australia and the University of NSW have found muscle relaxants might reduce pain in the short term, but the effect is too small to be considered clinically meaningful and there's an increased risk of side effects.
Published in the British Medical Journal on Monday, the research showed the effects of long-term muscle relaxants remain unknown and yet they are the third most frequently prescribed drugs for lower back pain, a major cause of disability worldwide.
Professor James McAuley, Director of NeuRA's Centre for Pain IMPACT and the School of Health Sciences UNSW, said muscle relaxants might reduce pain in the short term but on average the effect is probably too small to be important and most patients would not be able to feel any difference in their pain if taking a placebo, or sugar pill.
"We were surprised by this finding as earlier research suggested that muscle relaxants did reduce pain intensity," Professor McAuley said.
"But when we included all of the most up to date research, the results became much less certain."
The research involved evidence from 31 randomised controlled trials, which involved more than 6500 participants and were published as recently as February, to investigate the efficacy of muscle relaxants.
Researchers urged for large, high-quality, placebo-controlled trials to further test the usefulness - or not - of muscle relaxants.