Taking painkillers for back pain? A new study stated that effectiveness and safety of commonly used painkillers (analgesics) for short bouts of low back pain remains uncertain.

Analgesics such as paracetamol, ibuprofen, and codeine are widely used to treat acute non-specific low back pain, defined as pain lasting less than six weeks. But evidence for their comparative effectiveness is limited.

"Our review of analgesic medicines for acute non-specific low back pain found considerable uncertainty around effects for pain intensity and safety," said researchers from the University of New South Wales in Australia.

In an analysis published by The BMJ, they noted that clinicians and patients "are advised to take a cautious approach to the use of analgesic medicines".

The researchers trawled scientific databases for randomised controlled trials comparing analgesic medicines with another analgesic, placebo, or no treatment in patients reporting acute non-specific low back pain.

From an initial 124 relevant trials, they included 98 randomised controlled trials published between 1964 and 2021 in their analysis. These involved 15,134 participants aged 18 and over and 69 different medicines or combinations.

The trials included non-steroidal anti-inflammatory drugs, paracetamol, opioids, anticonvulsant drugs, muscle relaxants and corticosteroids.

The researchers noted low or very low confidence in the evidence for reduced pain intensity after treatment with muscle relaxant tolperisone, anti-inflammatory drug aceclofenac plus muscle relaxant tizanidine, and the anti-convulsant drug pregabalin, compared with placebo.

Very low confidence was also noted in evidence for large reductions in pain intensity for four medicines, such as the muscle relaxant thiocolchicoside and anti-inflammatory drug ketoprofen, moderate reductions for seven medicines, including anti-inflammatory drugs aceclofenac, etoricoxib and ketorolac, and small reductions for three medicines including ibuprofen and paracetamol.

Low or very low confidence evidence suggested no difference between the effects of several of these medications. The researchers also noted moderate to very low confidence evidence for increased adverse events, such as nausea, vomiting, drowsiness, dizziness, and headache.