Paracetamol and anti-inflammatory medicines

The evidence

A Cochrane review of 10 trials (3,541 participants) found that paracetamol reduced pain by 3.2 points on a 100-point scale more than placebo (95% CI 1.0 to 5.4), against a minimal clinically important difference of 9 points. Function improved by 2.9 points. Adverse events overall were similar to placebo. Abnormal liver function tests were more common with paracetamol (70 against 18 per 1,000; risk ratio 3.79, 95% CI 1.94 to 7.39), though their clinical importance was uncertain ²⁰.

In practice

Most trials lasted three months or less, and the effect did not differ by dose ²⁰. The knee standard describes paracetamol as less effective than anti-inflammatories and suggests it for people at risk of harm from them ¹³. For an individual resident, a trial of paracetamol with a planned check on whether it made a difference is one way to find out.

The evidence

In a Sydney trial of 1,652 people with acute low back pain from 235 primary care centres, regular or as-needed paracetamol for up to four weeks did not shorten recovery compared with placebo (median 17, 17 and 16 days; hazard ratio for regular paracetamol against placebo 0.99, 95% CI 0.87 to 1.14) ²². A Cochrane review found high-quality evidence of no difference from placebo in acute back pain, and that it is uncertain whether paracetamol has any effect on chronic back pain ²¹.

In practice

The participants were adults attending general practice, not aged care residents. The trial was funded by the NHMRC and GlaxoSmithKline Australia ²².

The evidence

An overview of Cochrane reviews found that in chronic musculoskeletal pain, mainly hand and knee osteoarthritis, topical diclofenac over 6 to 12 weeks gave at least 50% pain relief to 60% of people against 50% with placebo (number needed to treat 9.8), and topical ketoprofen to 63% against 48% (number needed to treat 6.9). Local skin reactions were more common than with placebo ²³.

In practice

The knee standard suggests a topical anti-inflammatory or capsaicin as an addition to other treatment and as part of short-term self-management ¹³.

The evidence

In meta-analyses of individual data from randomised trials, every anti-inflammatory regimen studied roughly doubled the risk of heart failure and increased upper gastrointestinal complications such as bleeding and perforation. A coxib or high-dose diclofenac increased major vascular events by about a third: for every 1,000 people treated for a year, about three more had a major vascular event, one of them fatal. High-dose naproxen did not significantly increase major vascular events ²⁴. The knee standard lists oral anti-inflammatories as first-line after a risk assessment, preferred to paracetamol because they work better, at the lowest effective dose for the shortest time ¹³.

In practice

Whether a short course is reasonable depends on the person’s heart, kidney and stomach history and their other medicines, including blood thinners. That is a decision for the prescriber with the resident.