Paracetamol: largely ineffective and not exactly safe

Effective and safe? This leader in pain research asks pharmacists to think again about this widely used drug

While paracetamol has been the ‘go-to’ medicine for acute and chronic pain conditions for many years, evidence shows the drug “doesn’t work” says Professor Andrew Moore, who is the Director of Pain Research at the University of Oxford.

In a guest blog published on Evidently Cochrane, Professor Moore says evidence for use of paracetamol in acute or chronic pain conditions such as back pain, osteoarthritis, neuropathic pain, cancer pain, postoperative pain and migraine is lacklustre.

“So how does paracetamol stack up against what people with acute back pain want? A Cochrane review is unequivocal – it doesn’t work. Not immediately, not later.

“Nor does the review find any evidence that it works in chronic back pain either.”

He says most recent best evidence for its use in osteoarthritis indicates a “barely significant and tiny benefit” over placebo, and there is a “complete lack of any evidence for paracetamol at all” to treat chronic neuropathic pain.

Paracetamol is useless for cancer pain, and barely helps in acute postoperative pain and migraine, he adds.

“That makes it time to start using our brains. We have probably given up thinking about paracetamol because it is over 50 years old, and we have it drummed into us that ‘at least it is safe’. Well the safety message may not be true either,” says Professor Moore.

He points out that emerging evidence shows:

  • Paracetamol is associated with increased mortality, cardiovascular adverse events, gastrointestinal adverse events, and renal impairment.
  • Non-overdose paracetamol exposure resulted in twice the rate of acute liver failure leading to registration for transplantation than NSAIDs.
  • Chronic pain patients taking paracetamol were four times more likely to have abnormal results on liver function tests than those taking placebo.
  • Arthritis patients show similar adverse event rates for paracetamol and ibuprofen over three months.

“The bottom line is that paracetamol doesn’t effectively relieve pain but has demonstrable rare but serious adverse effects,” concludes Professor Moore.

“If it were just a few tablets, then maybe we could ignore it, but it isn’t. Paracetamol consumption is measured not in kilograms, not even tons, but thousands of tons a year.”

Professor Moore’s comments come at the same time research reveals an association between paracetamol during pregnancy and increased risk of multiple behavioural problems in children.

The research, published in JAMA Paediatrics, found the children of mothers who used paracetamol at 18 and 32 weeks of pregnancy were more likely to have conduct problems and hyperactivity symptoms, while the children of mothers who took paracetamol at 32 weeks were also more likely to have emotional symptoms and total difficulties.

Read Professor Moore’s full post here.

Read about paracetamol and behavioural problems in children here.

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  1. John Cook

    Professor Moore is simply wrong about the safety issues he cites. These are from retrospective studies that have been disproven by recent meta-analyses of prospective trials. The only (rare) issue with Paracetamol shown in these prospective analyses is liver toxicity for which we are all mindful of anyway. Of course retrospective analyses will show higher rates of Gastrointestinal, Cardiovascular and Renal issues as all current guidelines recommend prescribing Paracetamol preferentially to NSAIDs to those at risk of these problems.
    Metaanalyses are often prone to publication bias, and when compared to NSAIDs this is likely as some prospective trials for NSAIDs are for medications that were patented at the time of study. Studies for these medicines which showed stronger effects for NSAIDs and weaker effects for Paracetamol would be more likely to be published as demonstrated by initiatives such as ALLTRIALS.
    I think abandoning Paracetamol for elderly osteoarthritis patients would be a big mistake and would be likely to cause harm. Pharmacy thought leaders should be careful to encourage Pharmacists and Prescribers to follow current treatment guidelines which recommend Paracetamol first line in Osteoarthritis.

    • Alan Windsor

      Medical cannabis……….Safe…effective….and cheap

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