Research shows paracetamol of little or no value for lower back pain and osteoarthritis, guidelines questioned

Research published today in The BMJ shows that taking paracetamol for treating lower back pain and osteoarthritis of the hip or knee is ineffective and may affect the liver.  

Lower back pain is the leading cause of global disability and affects around 10% of the population at any one time. Osteoarthritis is the most common form of arthritis and is the 11^th high contributor to global disability.  

Lead author, Gustavo Machado of The George Institute and the University of Sydney says the results of this research provide the impetus to review guidelines that endorse using paracetamol for lower back pain and osteoarthritis.

“Paracetamol is the most widely used over-the counter medicine for musculoskeletal conditions around the world, so it is essential that treatment recommendations are reviewed in light of this research,” says Mr Machado.

“Our findings also showed that paracetamol for lower back pain and osteoarthritis was associated with higher risk of liver toxicity,” he says. “Patients were nearly four times more likely to have abnormal results on liver function tests compared to those taking placebo pills.”

Senior author Associate Professor Manuela Ferreira of the George Institute for Global Health and the University of Sydney says there is an increasing amount of evidence questioning conventional treatments for back pain and other musculoskeletal conditions.

“For example, last year The George Institute showed that paracetamol does not speed recovery or reduce pain for acute low back pain,” says Associate Professor Ferreira. “This latest research, the most comprehensive systematic review of its kind, reaffirms this with an even larger, global patient base, and has for the first time also established that the effects of paracetamol for knee and hip osteoarthritis are too small to be of clinical importance.”

“We are also seeing increasing evidence examining early medical imaging for low back pain, which can cost up to $220 million a year in Australia, that shows that this procedure isn’t always necessary,” she says. “We urgently need to take stock of the evidence for common musculoskeletal conditions, a largely under-recognised health priority, and make sure people are receiving appropriate care.” 

Osteoarthritis expert, Professor David Hunter of the University of Sydney says this new research demonstrates the importance of reviewing paracetamol guidelines for treating osteoarthritis.

“A separate study published* recently has shown that paracetamol can be associated with an increasing incidence of mortality and increased risk of cardiovascular, gastrointestinal and renal disease in the general adult population,” says Professor Hunter.

“Clinicians should carefully weigh benefits and harms when making treatment decisions. Paracetamol is not efficacious and potentially harmful. In this context we cannot justify its continued use for these prevalent diseases.”

Paracetamol is currently recommended by most international clinical guidelines as a first line treatment for low back pain and osteoarthritis.

Other treatments known to be effective for patients with low back pain include advice and education programs, physical therapies such as spinal manipulation and exercise as well as psychological therapies such as cognitive behavioural therapy.

Land or water-based aerobic exercise, strengthening exercise, weight management and oral or topical anti-inflammatory medicines have been shown to provide benefit for patients with lower limb osteoarthritis.