Expect analgesic failure; pursue analgesic success

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.

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.