Paracetamol is ‘clinically ineffective’ for treating pain in patients with osteoarthritis and should not be prescribed by GPs, claim researchers.
The team, which conducted a meta-analysis of 74 randomised clinical trials that investigated 22 different interventions of NSAIDs or paracetamol against a placebo, found that paracetamol had only a very small effect on pain – often with little difference to the placebo – and did not reach the minimum clinically important difference for pain at any dose.
Diclofenac was the most effective for treating pain in osteoarthritic patients, having a 100% chance of reaching a clinical important difference when given at a 150mg daily dose, and was superior to maximum doses of frequently used NSAIDs, including ibuprofen, naproxen and celecoxib.
The paper said: ‘Our analysis suggests that paracetamol is clinically ineffective and should not be recommended for the symptomatic treatment of osteoarthritis, irrespective of dose.
‘Diclofenac at the maximum daily dose of 150mg per day is most effective for the treatment of pain and physical disability in osteoarthritis.’
But the researchers, from the University of Bern, warn that their study analysed short-term treatments only, and diclofenac should not be used in the long term due to the increased risk of cardiovascular events that it poses.
The paper, published in the Lancet, concluded: ‘In view of the well-established harms of NSAIDs and the treatment duration in almost all the trials included in this analysis, intermittent short-term use of NSAIDs in moderate to maximum doses as required should be given preference over long-term fixed dose.’
The majority of the included trials had a follow-up of three months or less, but the researchers believe that this was adequate as it ‘is an accurate representation of clinical practice’ where NSAIDs are prescribed on a short- to mid-term basis due to their established gastrointestinal and cardiovascular harms.
There has been previous contention for using paracetamol to treat osteoarthritis. NICE recommended against using paracetamol in a guidance draft in 2013, before opposition from experts in the musculoskeletal field led to a U-turn – largely due to the harms posed by using stronger analgesics.
But last year, Australian researchers reported that while paracetamol did show a statistically significant effect in reducing pain and disability in the short term, the changes were not clinically important.