Despite the ongoing popularity of medicines to treat low back pain, considerable uncertainty remains around their overall impact on pain relief and safety, a new study has found.
In a paper published today in the British Medical Journal, researchers from UNSW Sydney, Neuroscience Research Australia (NeuRA) and Brunel University London looked at 69 different medicines or combinations of analgesic medicines to compare their effectiveness for adults with acute low back pain. The study was a meta-analysis - it reviewed 98 trials, making it the most comprehensive evaluation of its kind to inform clinical decision making.
The medicines examined included non-steroidal anti-inflammatory drugs, paracetamol, opioids, anticonvulsants, antidepressants, skeletal muscle relaxants and corticosteroids. The study revealed that despite the ongoing popularity of these medicines to treat low back pain, when they were compared with placebo, there was considerable uncertainty around their overall impact on pain relief and safety.
The researchers also found that some analgesic medicines could increase the risk of adverse events or side effects, which can include nausea, dizziness and drowsiness.
Professor James McAuley, Director for the Centre for Pain IMPACT at NeuRA and UNSW’s School of Health Sciences, said the study recognises the complexities in acute low back pain and treatment.
“Despite more than 60 years of research, we are still uncertain whether any analgesic medicine provides meaningful pain relief for people with low back pain. We recommend that doctors and patients take a cautious approach to managing acute low back pain with analgesic medicines until higher quality trials of head-to-head comparisons are available."
A comprehensive analysis
The study analysed 98 randomised controlled trials (involving 15,134 participants in total) published between 1964 and 2021 of adults with acute non-specific low back pain. These included trials that compared an analgesic medicine directly with another analgesic medicine, a placebo, or no treatment at all across a total of 69 different medicines or combinations.
Dr Michael Wewege, a research fellow at NeuRA and a lead author of the study said the research team looked at nearly 60 years of research involving over 15,000 participants.
“Although previous reviews have evaluated analgesic medicines compared with a placebo, very few have compared the effectiveness of these medicines as a whole. Our rigorous method ensured as much data as possible could be taken into account,” said Dr Wewege.
Dr Neil O’Connell of Brunel University London said, “it is quite shocking that the evidence base for the effectiveness and safety of some of the most commonly used drugs for such a common condition is so fragile and incomplete. Our findings clearly indicate the need for larger, rigorous trials that can genuinely inform better clinical decisions."
Number one cause of disability
Back pain continues to be the number one cause of disability worldwide, costing the Australian health system an estimated $4.8 billion every year. According to the Royal College of General Practitioners, musculoskeletal concerns are the second-most common reason for GP visits, after psychological concerns.
The vast majority of people who visit their doctor for acute non-specific low back pain, which is defined as low back pain that lasts fewer than six weeks, are prescribed an analgesic to manage their symptoms (61 per cent of patients in Australia and 48 per cent in the UK).
Implications for clinicians
Low back pain is one of the main reasons people visit their GP. Clinical practice guidelines recommend advice, reassurance, encouragement of physical activity, and self-management of symptoms as first-line care, whilst analgesic medicines and physical therapy are second-line interventions.
“Patients should be reassured that acute low back pain is very likely to resolve by itself over time, regardless of whether or not they take medicines,” said Professor McAuley.
“If analgesic medicines are required, our study shows that clinicians should take a cautious approach and importantly, make this decision in consultation with patients on their specific pain experience, severity of symptoms and their individual needs and preferences.”