More adverse headlines cropped up in June 2016 after a Cochrane review considered paracetamol’s role in low back pain (LBP).⁶ Having sifted through more than 4,000 papers for potential inclusion in the study, three studies met the criteria, which were:

• Placebo-controlled randomised trials
• Involving patients with non-specific acute, sub-acute, or chronic non-specific LBP
• Patients without serious spinal pathology
• Patients who were not pregnant.

These three studies from the USA, Austria, and Australia had a combined total of over 1,800 participants (although the Austrian study with 36 participants has since been retracted) with an average age of mid-40s.^7,8,9 Treatment duration included single doses, two consecutive days, and daily until recovered to a maximum of four weeks.

The Australian researchers had commented: “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.”⁹

Assessing primary outcomes for acute LBP from the three papers, the Cochrane researchers said there was “high-quality evidence” that there is no difference between paracetamol (4g per day) and placebo for pain or disability at one week. Nor did paracetamol have any effect on the physical component of quality of life at four weeks and nor was there any difference
in sleep quality at one week or 12 weeks. Note, though, that adverse events were reported by 19 per cent of participants, but with no difference between paracetamol and placebo.⁶

For chronic LBP, the Cochrane researchers cited only one trial with 72 participants, saying the evidence was of “very low quality” but it suggested paracetamol had no effect on pain intensity.

Discussing the overall findings, the Cochrane paper notes that none of the trials followed patients for more than 12 weeks. In addition, more than 90 per cent of patients were in one trial “which included middle-aged Australian participants with acute LBP; thus care should be taken when generalising the findings of this review to other types of patients, such as chronic LBP patients.”