Analysis

Expect analgesic failure; pursue analgesic success

BMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f2690 (Published 03 May 2013) Cite this as: BMJ 2013;346:f2690
  1. Andrew Moore, professor1,
  2. Sheena Derry, senior research officer1,
  3. Christopher Eccleston, professor2,
  4. Eija Kalso, professor3
  1. 1Pain Research and Nuffield Division of Anaesthetics, University of Oxford, Churchill Hospital, Oxford OX3 7LJ, UK
  2. 2Centre for Pain Research, University of Bath, Bath, UK
  3. 3Pain Clinic, Department of Anaesthesiology, Helsinki University Central Hospital, Finland
  1. Correspondence to: R A Moore andrew.moore{at}ndcn.ox.ac.uk
  • Accepted 2 April 2013

Most analgesic drugs work well but in only a small percentage of people. Andrew Moore and colleagues argue that we need to move away from a focus on average response and seek out what works for each patient

A 2003 newspaper article caused considerable grief for the pharmaceutical industry. Entitled, “Our drugs do not work on most patients,1 it claimed that most drugs worked in only 30-50% of people. While that surprised journalists and the public, it was not news to professionals, including the then editor of the BMJ.2

Individual patient responses vary greatly, as a clinical trial of pregabalin in fibromyalgia shows (fig 1). Pain relief is not normally distributed but usually bimodal, being either very good (above 50%) or poor (below 15%).3 4 5 Using averages is unhelpful and misleading, because “average” pain relief is actually experienced by few (if any) patients, and it tells us nothing about how many patients will experience clinically useful pain relief. Research is therefore moving to responder analyses—reporting the proportion of patients achieving outcomes that patients consider worthwhile.

Fig 1 Individual changes in pain over 14 weeks of treatment with pregabalin 450 mg in 200 patients with fibromyalgia

In this article we examine rates of success and failure of drugs used in treating pain. We suggest a radical rethink of achievable analgesic effects, and explore how anticipating and recognising analgesic failure will help improve the management of pain. This approach is relevant to all painful conditions, but here we use examples from acute postoperative pain, headache, and chronic musculoskeletal and neuropathic pain.

Measuring effectiveness

Patients want large reductions in pain intensity (typically at least 50%, ideally no worse than mild pain6), with relief from associated problems such as sleep disturbance and depression but without common adverse …

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