Paracetamol is no better than placebo pills at tackling acute back pain, new research has indicated.

The research findings have called into question the common belief that paracetamol should be the first choice painkiller for low-back pain. The researchers indicate that paracetamol may not be effective for back pain but can be effective for other types of pain.

The Australian study concluded that paracetamol is no better than placebo at helping recovery from acute episodes of lower back pain or improving pain levels, function, sleep, or quality of life.

The Paracetamol for Low-Back Pain Study (PACE) assigned 1,652 people with acute low-back pain in Sydney, Australia to receive up to four weeks of paracetamol in regular doses (three times a day), paracetamol as needed for pain or placebo.

All patients received advice and reassurance and were followed up for three months.

Low-back pain is the leading cause of disability worldwide and most clinical guidelines recommend paracetamol as the first choice medicine for acute low-back pain.

However, this was despite the fact that no previous studies have provided concrete evidence that paracetamol is effective in people suffering from low-back pain.

The researchers found there were no differences in the number of days to recovery between the different groups of patients studied.

Average time to recovery was 17 days in the regular paracetamol group, 17 days in the taken-as-needed paracetamol group, and 16 days in the placebo group.

It was also found that paracetamol had no effect on short-term pain levels, disability, function, sleep quality, or quality of life.

"Simple analgesics such as paracetamol might not be of primary importance in the management of acute lower back pain", said lead author Dr Christopher Williams from the George Institute for Global Health at the University of Sydney.

"The results suggest we need to reconsider the universal recommendation to provide paracetamol as a first-line treatment for low-back pain, although understanding why paracetamol works for other pain states but not low-back pain would help direct future treatments," he added.

Dr Williams said it would be interesting to see whether advice and reassurance might be a more effective than pharmacological strategies for acute episodes of low-back pain.

The research is published in The Lancet.