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Efficacy of wide range of oral analgesic drug/dose combinations quantified

Reuters Health • The Doctor's Channel Daily Newscast

NEW YORK (Reuters Health) – While no oral analgesic works well in all individuals, a single dose of 600 mg ibuprofen will cut postop pain at least in half for 77% of patients, while a 600-mg dose of aspirin produces the same effect in only 39% of patients.

Those examples come from an overview of 35 separate Cochrane Reviews examining the efficacy of 46 analgesic drug/dose combinations in relieving severe to moderate pain after surgery, molar extraction, or other painful conditions.

The results “should inform choices by professionals and consumers,” conclude Dr. R. Andrew Moore, at the University of Oxford, UK, and colleagues in their exhaustive report in the Cochrane Library issue published online September 7.

The analysis summarizes data from 350 individual studies involving about 45,000 participants, comparing a single dose of an oral analgesic versus a placebo, in which the primary outcome was the percentage of patients with at least 50% pain relief over 4-6 hours. The authors extracted the number needed to treat (NNT) for this outcome for each drug/dose combination, as well as the time to remedication.

As mentioned, efficacy rates varied from about 30% to over 70%, with the lowest being 14% for codeine, the report indicates. Time to remedication ranged from 2 hours to 20 hours.

NNTs to provide one patients with at least 50% pain relief varied from 1.5 to 20. Examples of drugs with low NNTs included ibuprofen 400 mg (NNT 2.5), etoricoxib 120 mg (NNT 1.9) and codeine 60 mg plus acetaminophen/paracetamol 1000 mg (NNT 2.2), according to the report.

Regarding safety, the authors found that adverse events were infrequent and generally no different between active drugs and placebos, except in the case of opioids and aspirin.

The report also includes information on drugs for which data are inadequate or unreliable.

Dr. Moore and colleagues point out that some of the dosages included in the analysis are not typically used, and some of the drugs are not available everywhere. However, “All data are presented so that readers can use that which is relevant for them.”

They conclude, “There is a wealth of reliable evidence on the analgesic efficacy of single dose oral analgesics.”

Dr. Moore added in a Cochrane press release: “If the first pain killer a person tries doesn’t seem to be working, then a doctor should look to find an alternative reliable drug and see if it is more effective in that individual patient. There are plenty of options that have a solid evidence base.”

Reference:
Single dose oral analgesics for acute postoperative pain in adults
Cochrane Database Syst Rev 2011, Issue 9.