A large study has found that taken on its own, paracetamol has no role to play in the treatment of the most common form of arthritis, as it is ‘not clinically effective'.

Osteoarthritis, also known as degenerative joint disease, is the most common type of arthritis. The main symptoms are pain and stiffness. Most Irish people over the age of 55 have evidence of the condition at some joint in their body. The most common weight-bearing joint affected by the condition is the knee.

Paracetamol, along with NSAIDs (non-steroidal anti-inflammatory drugs), such as ibuprofen, are often used as a first-line treatment for mild to moderate pain caused by osteoarthritis. However, as there are more side-effects with NSAIDs, paracetamol tends to be used more often in the long-term.

Swiss researchers decided to assess the effectiveness of various treatments. They pooled data from over 70 trials that had been published between 1980 and 2015. These trials involved more than 58,500 people with osteoarthritis.

The researchers compared the effects of 22 different treatments, as well as placebo. These treatments included different doses of paracetamol and seven NSAIDs.

The study found that all 22 treatments improved symptoms of pain when compared with placebo, irrespective of the dose given.

However when it came to paracetamol, while the drug was found to be slightly better than placebo, it did not meet the minimum standards of clinical effectiveness in reducing pain or improving physical function among those with knee and hip osteoarthritis.

"NSAIDs are usually only used to treat short-term episodes of pain in osteoarthritis, because the side-effects are thought to outweigh the benefits when used longer term. Because of this, paracetamol is often prescribed to manage long-term pain instead of NSAIDs. However, our results suggest that paracetamol at any dose is not effective in managing pain in osteoarthritis," commented Dr Sven Trelle of the University of Bern.

He noted that some NSAIDs were effective and so could be used ‘intermittently without paracetamol'.

"NSAIDs are some of the most widely used drugs for patients with osteoarthritis. There is a range of different drugs at different dosages that doctors can prescribe, but patients often switch between drugs, or stop taking them because the first one they use hasn't sufficiently helped control the pain. We hope our study can help better inform doctors about how best to manage pain in this population," Dr Trelle said.

Details of these findings are published in the journal, The Lancet. In a linked comment, Prof Nicholas Moore of the University of Bordeaux in France, added that many patients ‘may be suffering needlessly because of perceived NSAIDs risks and paracetamol benefits, which might not be real'.