Taking ibuprofen for a bad back could increase the chances of developing long-term pain, a study has found.
Analysis of 500,000 UK adults showed that those taking anti-inflammatory painkillers such as ibuprofen to treat back pain had a 70 per cent higher risk of developing long-term pain, compared to those who had used alternatives like paracetamol.
The researchers believe that anti-inflammatories may dampen an immune system response which repairs damage.
Jeffrey Mogil, a professor of pain studies at McGill University in Canada, said: "For many decades it's been standard medical practice to treat pain with anti-inflammatory drugs.
"But we found that this short-term fix could lead to longer-term problems."
Researchers followed 98 patients with acute low back pain for three months to understand the transition from acute to chronic low back pain.
The academics also studied laboratory mice and found that there was a reduction in the activity of neutrophils - a type of white blood cell that assists to heal damaged tissues and resolve infections.
Blocking these cells in mice, using a special antibody, prolonged the pain up to 10 times the normal duration.
Treating the pain using anti-inflammatories produced a similar result, despite relieving pain early on.
Luda Diatchenko, a professor in the faculty of medicine, faculty of dentistry, and Canada Excellence Research chairwoman in human pain genetics, said data suggested painkillers like ibuprofen and steroids could increase the chances of developing chronic pain, but "proper clinical trials should be done to firmly conclude this."
"These findings should be followed up by clinical trials directly comparing anti-inflammatory drugs to other painkillers that relieve aches and pains but don't disrupt inflammation," she said.
In Britain, about 10 million people suffer back pain, with about 5.5 million in England suffering from severe pain that has lasted three months or more, an estimate from Imperial College London suggests.
Massimo Allegri, a physician at the Policlinico of Monza Hospital in Italy and Ensemble Hospitalier de la Cote in Switzerland, said: "Our findings suggest it may be time to reconsider the way we treat acute pain.
"Luckily, pain can be killed in other ways that don't involve interfering with inflammation."
The study, which looked at people who had signed up to the UK Biobank scheme, is published in the journal Science Translational Medicine.
