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Paracetamol ‘no better than placebo’ for acute low-back pain, claim researchers



There is ‘no evidence’ to support guideline-recommended use of paracetamol as the first-line analgesic for treating acute lower back-pain, researchers have found.

The study, published in the Lancet, said the first-line use of paracetamol for pain relief in acute lower back pain offers no improvement in recovery time compared with placebo following a randomised trial, causing researchers to question its use.

The researchers concluded that ‘advice and reassurance, rather than analgesics, should be the focus of first-line care’.

GP experts said the findings underscored the importance of not relying on analgesics.

Currently, NICE Clinical Knowledge Summaries advises offering paracetamol as the preferred option for analgesia to patients with acute low-back pain, while European guidance also endorses paracetamol as the first-line treatment for pain relief in acute, non-specific low-back pain.

But the latest study concluded: ‘Our findings suggest that regular or as-needed dosing with paracetamol does not affect recovery time compared with placebo in low-back pain, and question the universal endorsement of paracetamol in this patient group.’

The Australian researchers studied 550 patients with new-onset acute low-back pain of less than six week’s duration, who were randomly assigned to take paracetamol as-needed, paracetamol regularly three times a day or a placebo, for four weeks.

All the patients were given advice to remain active and avoid bed rest, and reassurance that acute low-back pain generally has a favourable prognosis.

The researchers found the median time to recovery was no different among the groups, taking 17 days among patients taking paracetamol as-needed, 17 days among patients taking regular doses of paracetamol and 16 days in the placebo group.

They also found no differences for a range of secondary outcomes – including pain intensity, disability, symptom change and function.

They added the caveat that ‘these results should be replicated before paracetamol is completely dismissed in the management of low-back pain’.

The latest research comes after NICE advisors on osteoaorthritis guidelines raised concerns paracetamol was not as beneficial as previously thought, and was associated with increased adverse events, especially when used in combination with an NSAID.

NICE was forced to rethink plans to drop paracetamol as the first-line analgesic option, however, after musculoskeletal and pain experts warned against the move without further evaluation, citing fears it could lead to many patients being swapped inappropriately onto opioids.

Authors of the current Lancet study said the safety profile of paracetamol ‘is favourable’ compared with other analgesics such as NSAIDs, and that these alternatives are in any case only marginally better than placebo for low-back pain, so ‘it is not clear which drug should be preferred for management of low-back pain’.

They concluded: ‘Our results convey the need to reconsider the universal endorsement of paracetamol in clinical practice guidelines as first-line care for low-back pain, and suggest that advice and reassurance, rather than analgesics, should be the focus of first-line care.’

Dr John Dickson, community rheumatologist and a former GP who is a member of the Primary Care Rheumatology Society steering group, told Pulse the study reinforced his concerns that paracetamol in particular is ineffective for musculoskeletal and other types of pain, and agreed that advice to stay active is key.

He said: ‘Paracetamol doesn’t work in other conditions either – it’s just a placebo effect. But I would agree back pain doesn’t want to be treated with medication anyway – exercise is the way actually.’ 

Dr Martin Johnson, RCGP clinical lead on chronic pain, agreed that the evidence is limited for analgesics in low-back pain but stressed that individual responses to analgesics may vary greatly among patients.

Dr Johnson said: ‘The message here is, make sure you reinforce with correct advice rather than just reaching for the prescription pad.’

He added: ‘I don’t think this would stop me prescribing – one of the issues is that there is a slight swing away from RCTs because, particularly with analgesics, the individual response is so powerful.  But it’s what you tell people rather than write into your keypad and prescribe that’s important.’

Lancet 2014; available online 24 July