This overview is an update of a 2011 Cochrane overview of Single dose oral analgesics for acute postoperative pain in adults. The aim of the overview is to summarise the efficacy of pharmaceutical interventions for acute pain in adults with at least moderate pain following surgery who have been given a single dose of oral analgesic.

Methods

All Cochrane reviews of RCTs of single dose oral analgesics for acute postoperative pain in adults (aged 15 years and over) were considered. Two reviewers independently selected reviews, assessed methodological quality and extracted data. Methodological quality was assessed using criteria adapted from AMSTAR (Assessing the Methodological Quality of Systematic Reviews). Adverse event information was collected and included in a separate review.

• Results
• 39 Cochrane reviews investigating 41 analgesics or analgesic combinations were included.
• The number of individual studies included in the reviews is around 460 with 50,000 unique participants.
• The individual reviews included only high-quality trials of standardised design, methods, and efficacy outcome reporting.
• Reliable results (high quality information) were obtained for 53 pairs of drug and dose in painful postsurgical conditions; these included various fixed dose combinations, and fast acting formulations of some analgesics.
• NNTs varied from about 1.5 to 20 for at least 50% maximum pain relief over four to six hours compared with placebo.
• The proportion of participants achieving this level of benefit varied from about 30% to over 70%, and the time to remedication varied from two hours (placebo) to over 20 hours.
• Good (low) NNTs were obtained with
  • ibuprofen 200 mg plus paracetamol (acetaminophen) 500 mg (NNT compared with placebo 1.6; 95% confidence interval 1.5 to 1.8),
  • ibuprofen fast acting 200 mg (2.1; 1.9 to 2.3);
  • ibuprofen 200 mg plus caffeine 100 mg (2.1; 1.9 to 3.1),
  • diclofenac potassium 50 mg (2.1; 1.9 to 2.5), and
  • etoricoxib 120 mg (1.8; 1.7 to 2.0).
• For comparison, ibuprofen acid 400 mg had an NNT of 2.5 (2.4 to 2.6). Not all participants had good pain relief and, for many pairs of drug and dose, 50% or more did not achieve at least 50% maximum pain relief over four to six hours.
• Long duration of action (eight hours or greater) was found for etoricoxib 120 mg, diflunisal 500 mg, paracetamol 650 mg plus oxycodone 10 mg, naproxen 500/550 mg, celecoxib 400 mg, and ibuprofen 400 mg plus paracetamol 1000 mg.
• There was no evidence of analgesic effect for aceclofenac 150 mg, aspirin 500 mg, and oxycodone 5 mg (low quality evidence). No trial data were available in reviews of acemetacin, meloxicam, nabumetone, nefopam, sulindac, tenoxicam, and tiaprofenic acid. Inadequate amounts of data were available for nine drugs and doses, and data potentially susceptible to publication bias for 13 drugs and doses (very low quality evidence).

Conclusions

The authors concluded:

There is a wealth of reliable evidence on the analgesic efficacy of single dose oral analgesics. Fast acting formulations and fixed dose combinations of analgesics can produce good and often long-lasting analgesia at relatively low doses. There is also important information on drugs for which there are no data, inadequate data, or where results are unreliable due to susceptibility to publication bias. This should inform choices by professionals and consumers.

Comments

Yesterday we looked at the review of adverse effects of single dose oral analgesics for acute postoperative pain (Dental Elf 19^th– Oct 2015). This overview conducted in parallel pulls together a very large amount of high quality information regarding the efficacy of analgesics in all types of surgery. The authors highlight that even the most effective drugs fail to provide good analgesia to some patients so that some degree of analgesic failure should be anticipated, indeed with many it may be as higher than half of those treated. This overview has only included Cochrane reviews and it should be noted that there are no Cochrane reviews for some commonly used drugs e.g. Tramadol. In addition while the Cochrane review have been updated since 2008 many have not added any new studies. In their detailed conclusions that authors state:-

There is also a clear message that simple drug combinations and fast acting formulations can deliver good analgesia in many people with acute pain at relatively low doses.

Because some drugs do not work fro some people in some situations they also note that;

Failure to achieve good pain relief should be actively and regularly sought and rectified.

Links

Moore RA, Derry S, Aldington D, Wiffen PJ. Single dose oral analgesics for acute postoperative pain in adults – an overview of Cochrane reviews. Cochrane Database of Systematic Reviews 2015, Issue 9. Art. No.: CD008659. DOI: 10.1002/14651858.CD008659.pub3.

Dental Elf 19^th– Oct 2015 – Few adverse events with single dose oral analgesics for acute postoperative pain