An review of the evidence by Australian authors has placed paracetamol back in the spotlight yet again, adding more fuel to the debate on whether it should be struck from guidelines for osteoarthritis.
The systematic review and meta-analysis involving 13 randomised controlled studies found little evidence that paracetamol worked for osteoarthritis or lower back pain compared to placebo.
Writing in the BMJ the authors from The George Institute for Global Health say this latest evidence “provides an argument to reconsider the endorsement of paracetamol in clinical practice guidelines for low back pain and hip or knee osteoarthritis.”
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Recent evidence on lower limb osteoarthritis showed that exercises (such as strengthening exercise) compared with no exercise control result in large treatment effects for pain reduction (mean difference −2.3, 95% confidence interval −2.8 to −1.26; on a 10 cm visual analogue scale).
“This effect size is much larger than the largest effect size from our pooled analyses on short term effects of paracetamol for hip or knee osteoarthritis,” they wrote in the BMJ.
Paracetamol alone therefore might not be sufficient to treat hip or knee osteoarthritis and might need to be accompanied by other management strategies, such as exercises and advice/education, they said.
The meta-analysis found that for lower back pain, paracetamol had no effect and did not reduce disability or improve quality of life compared with placebo.
It also found “high quality” evidence that paracetamol has a significant but small effect in patients with hip or knee osteoarthritis compared with placebo in the short term.
However “the small effects, <4 points on a 0-100 point scale, are not likely to be meaningful for clinicians or patients,” they said.
They also found that paracetamol use in osteoarthritis increase abnormal results on liver function tests almost four-fold but the clinical relevance of this was uncertain, the authors wrote in the BMJ.
An accompanying editorial from Christian Mallen and Elaine Hay from Keele University say the study “re-opens the debate” on the effectiveness and safety of paracetamol.
But if paracetamol were taken off existing guidelines this would lead to an increase in the use of other drugs such as opioids.
Instead they call for the use of safe and effective alternative treatments such as exercise, which has clear benefits in the management of spinal pain and osteoarthritis.