Is Paracetamol effective against back pain?

In primary schools in West Glamorgan 64 per cent of children admitted they had suffered back pain. Leading physiotherapists warn of an impending ‘back injury timebomb’ as children lead increasingly sedentary lifestyles with the advent of video games and smartphones. Even sportspeople are not exempt: Tiger Woods was recently seen clutching his golf club like a cane as he exited a tournament due to back pain. When the pain hits, rest, ice, heat, massage, creams, pilates and home remedies can all help. Sometimes, however, medical treatment is needed and national clinical guidelines throughout the world recommend paracetamol as the drug of first choice in treating lower back pain.

A recent widely-publicised article in the British Medical Journal examined data from 3 clinical trials, involving nearly 2000 people, and suggested that paracetamol is ineffective in treating lower back pain. Worryingly, it also showed that patients taking paracetamol are nearly four times more likely to have abnormal liver blood tests, even when staying within the recommended daily maximum dose. Whether these blood results lead to actual clinical symptoms in the long term is unknown, but warrants testing since paracetamol toxicity is the leading cause of acute liver failure in the Western World.

What’s more, we don’t really know how paracetamol works: it may work in a similar way to aspirin by blocking production of hormones called prostaglandins involved in pain and inflammation. But unlike aspirin, it does not thin the blood nor irritate the stomach, so must work slightly differently: maybe even directly affecting neurotransmitters in the brain. This could explain a recent study, in which paracetamol was thought to ‘blunt both positive and negative emotions’?

Paracetamol was discovered in 1884 (by chance when investigating a cure for intestinal worms), “rediscovered” in the 1950s, and has been one of the world’s most widely used painkillers since the 1980s. It is available in tablet, capsule, liquid, suppository, injection and effervescent forms. It is effective in treating headaches, post-operative pain, cancer pain (in combination with opioids), and in reducing fever associated with colds and flu. The back-pain article questioned the use of paracetamol for episodes of acute back pain (less than six weeks) with patients mostly under the age of 55: what about more long-term, less severe back pain, in the elderly? One trial mentioned did not report results for the placebo group, making it hard to judge the real effects of paracetamol; another has since been retracted from publication.

The National Institute for Health and Care Excellence does still advocate paracetamol for back pain, until further studies are completed; and it may have even more exciting uses than first imagined: studies are testing whether it can reduce prostate cancer, limit damage after heart attacks and strokes, and have anti-diabetic actions. Perhaps it is time to take a fresh look at an old favourite in the drug cabinet. Meanwhile, the best approach to back pain is to protect the back from damage from a young age.

Helen Cowan studied human physiology at Oxford University from 1996-1999 then completed a PhD in cardiac pharmacology at Oxford in 2002. She is also a qualified nurse and has worked widely in cardiac surgery, neurosurgery, clinical trials and elderly care. She is a freelance writer and has published in the British Journal of Cardiac Nursing, worked as a columnist in the Nursing Times, and written for local and online publications. She is fascinated by the workings of the human body.