Geneva, Mar 19: Paracetamol does not meet the minimum standard of clinical effectiveness in reducing pain or improving physical function in patients with knee and hip osteoarthritis, a new study has found.
Although paracetamol was slightly better than placebo, researchers from University of Bern in Switzerland said that taken on its own, paracetamol has no role in the treatment of patients with osteoarthritis - the leading cause of joint pain and stiffness in older people - irrespective of dose.
The study was the largest analysis of randomised trials of medical pain relief for osteoarthritis to date and found that diclofenac 150 milligrammes per day, a non-steroidal anti- inflammatory drug (NSAID), is the most effective short-term pain relief.
However, researchers caution against long-term use of NSAIDs because of known side-effects. Worldwide, 9.6 per cent of men and 18 per cent of women over the age of 60 have osteoarthritis.
Osteoarthritis can impair physical activity, which increases patients' risk of obesity, cardiovascular disease, diabetes, and general ill-health, researchers said.
They pooled data from 74 randomised trials published between 1980 and 2015. With data from a total of 58,556 patients with osteoarthritis, the study 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. 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, researchers said.
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, and did not reach the minimum clinically important difference, researchers said.
In comparison, diclofenac at the maximum daily dose of 150 milligrammes/day was most effective for the treatment of pain and physical disability in osteoarthritis, and superior to the maximum doses of frequently used NSAIDs, including ibuprofen, naproxen, and celecoxib, they said.
"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," said Sven Trelle from University of Bern.
"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," he said. The findings were published in The Lancet.