Prescribing muscle relaxant drugs for low back pain gives only short-term relief and there is an increased risk of side-effects, new analysis claims today.
A report published in The BMJ says the effects of muscle relaxants are too small to be considered clinically meaningful, despite being commonly prescribed.
However, the research team in Australia say large trials are urgently needed to resolve uncertainties around their use.
They reviewed and completed a detailed analysis of 31 randomised controlled trials involving more than 6,500 participants, published up to February 2021, to establish the effectiveness, acceptability, and safety of muscle relaxants compared with placebo, usual care, or no treatment.
Using the recognised GRADE system, they set a difference of at least 10 points on a 0 to 100 point scale for pain and disability to be the smallest clinically important effect.
Very low certainty evidence showed that non-benzodiazepine antispasmodic drugs might reduce pain intensity at two weeks or less for patients with acute low back pain compared with controls.
But because the effect was less than eight points on the 0-100 point scale, it did not meet common thresholds to be clinically meaningful.
They also found there was little to no effect of non-benzodiazepine antispasmodics on pain intensity at three-13 weeks or on disability when the patients were followed up.
Low and very low certainty evidence showed that non-benzodiazepine antispasmodics might increase the risk of common side effects, such as dizziness, drowsiness, headache and nausea, and might have little to no effect on treatment discontinuation compared with controls.
They write: “We would encourage clinicians to discuss this uncertainty in the efficacy and safety of muscle relaxants with patients, sharing information about the possibility for a worthwhile benefit in pain reduction but increased risk of experiencing a non-serious adverse event, to allow them to make informed treatment decisions.
“Large, high quality, placebo controlled trials are urgently needed to resolve uncertainties about the efficacy and safety of muscle relaxants for low back pain.”
Orthopaedic evidence questioned
Meanwhile, another analysis in The BMJ shows that most common orthopaedic procedures are not backed up by high quality evidence.
A team of UK researchers used data from previous analyses of randomised controlled trials and other studies to compare the clinical effectiveness of the ten most common orthopaedic procedures – including included meniscal repair, shoulder rotator cuff repair, carpal tunnel decompression surgery, and total hip and knee replacements – with no treatment, placebo, or non-operative care.
They then went on to compare findings for each procedure with national guidelines to see if recommendations reflected the body of available evidence.
The researchers found randomised controlled trial evidence supported the superiority of carpal tunnel decompression and total knee replacement over non-operative care.
But no randomised controlled trials specifically compared total hip replacement or meniscal repair with non-operative care. Trial evidence for the other six procedures showed no benefit over non-operative care.
They say more research is urgently needed, particularly for procedures with a limited evidence base.
They write: “This will improve patient care, cut healthcare costs, permit more efficient use of our resources, and increase societal trust in orthopaedic interventions.”
Cashin AG, Folly T, Bagg MK et al. Efficacy, acceptability, and safety of muscle relaxants for adults with non-specific low back pain: systematic review and meta-analysis. BMJ 8 July 2021. DOI: 10.1136/bmj.n1446
Blom AW, Donovan RL, Beswick AD et al. Common elective orthopaedic procedures and their clinical effectiveness: umbrella review of level 1 evidence. BMJ 8 July 2021. DOI: 10.1136/bmj.n1511
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