The world’s most widely used over-the-counter pain reliever works no better than a placebo for lower back pain, according to a large study by researchers in Australia.
Paracetamol – also known as acetaminophen – is the active ingredient in Tylenol, Excedrin, and hundreds of other pain medications. It is often recommended by doctors worldwide for back pain, despite little scientific evidence that it is effective.
Now there’s proof that it doesn’t work.
In a study published in The Lancet, researchers randomly assigned over 1,600 patients with acute low back pain to one of three groups. The first group received up to 4 weeks of paracetamol in regular doses three times a day; the second group took paracetamol as needed for pain; and the third group received a placebo.
Paracetamol was found to have no effect on short-term pain levels, disability, function, sleep quality, or quality of life.
Patients in both groups that received paracetamol took about 17 days to recover from back pain, compared to 16 days in the group that took a placebo.
“Simple analgesics such as paracetamol might not be of primary importance in the management of acute lower back pain”, said lead author Christopher Williams, PhD, of the George Institute for Global Health at the University of Sydney in Australia.
“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.”
Low-back pain is the leading cause of disability worldwide. Clinical guidelines have long recommend paracetamol as the front line pain reliever for acute low-back pain.
“Williams and colleagues are to be applauded for tackling this research question on a topic that has been without debate and evidence for such a long time,” wrote Bart Koes, PhD, and Wendy Enthoven, PhD, from University Medical Center in the Netherlands, in a commentary also published in The Lancet.
“Although the findings from this high-quality trial are clear, the content of guidelines should not be changed on the basis of a single trial; more robust and consistent evidence, including verification of the results in other populations, is needed.”
The study was funded by National Health and Medical Research Council of Australia and GlaxoSmithKline Australia.
Over 50 million people in the U.S. use acetaminophen (paracetamol) each week to treat pain and fever.
Acetaminophen has long been associated with liver injury and allergic reactions such as skin rash. In the U.S. over 50,000 emergency room visits each year are caused by acetaminophen, including 25,000 hospitalizations and 450 deaths.