‘Paracetamol does not help kill pain’

In a largescale analysis of pain-relief medication for osteoarthritis, researchers found that popular drug paracetamol is not effective in reducing pain or improving physical function in patients with knee and hip osteoarthritis. Researchers found that paracetamol does not even meet the minimum standard of clinical effectiveness, though it was slightly better than placebo, researchers conclude that, taken on its own, paracetamol has no role in the treatment of patients with osteoarthritis, irrespective of dose. In fact it was found that diclofenac a non-steroidal anti-inflammatory drug (NSAID), is the most effective short-term pain relief.

The study, published in the Lancet, is the largest analysis of randomised trials of medical pain relief for osteoarthritis to date. Though the authors found diclofenac 150mg/day most effective, they caution against long-term use of NSAIDs because of known side-effects.

Worldwide, 9.6% of men and 18% of women over the age of 60 have osteoarthritis.

Estimates suggest that 26.9 million adults in the USA have the disease, and 8.75 million in the UK. Osteoarthritis is the leading cause of pain in elderly people. It can impair physical activity, which increases patients’ risk of obesity, cardiovascular disease, diabetes, and general ill-health.

Dr Sven Trelle from the University of Bern, Bern, Switzerland, and colleagues, pooled data from 74 randomised trials published between 1980 and 2015.

With data from a total of 58,556 patients with osteoarthritis, the study (a network meta-analysis) compared the effect of 22 different medical treatments and placebo on pain intensity and physical activity.

The 22 treatments included various doses of paracetamol and seven different NSAIDs [3].

Paracetamol and NSAIDs are usually the first line treatment for mild to moderate pain management in osteoarthritis, but paracetamol is used more frequently in the long-term because of the cardiovascular and gastrointestinal side effects associated with long-term NSAID use.

The analysis found that all 22 preparations of medications, irrespective of dose, improved symptoms of pain compared with placebo. Although some doses of paracetamol had a small effect on improving physical function and decreasing pain, the effect was only slightly better than placebo. In comparison, diclofenac at the maximum daily dose of 150 mg/day was most effective for the treatment of pain and physical disability in osteoarthritis (effect size –0.57), and superior to the maximum doses of frequently used NSAIDs, including ibuprofen, naproxen, and celecoxib.

According to Dr Trelle, “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, but that certain NSAIDs are effective and can be used intermittently without paracetamol.”