Pre‐operative analgesia — what is wrong with the evidence?

We read with interest McCartney’s and Chamber’s recent letter about which route of administration we should use for analgesics (Anaesthesia 1998; 53: 607–8). We should like to comment on two problems. First, although there is no obvious (i.e. intellectually comprehensible) reason why the rectal route should be preferred to oral, this way of giving drugs to adults seems increasingly popular with many anaesthetists [1, 2]. This odd preference may have less to do with logic than with misconceptions about pre-emptive analgesia, the belief that rectal administration may be less toxic (i.e. less gastroduodenal problems with nonsteroidal anti-inflammatory drugs), or the idea that rectal administration is pharmacokinetically advantageous because of a limited hepatic first-pass effect. Second, this discussion raises questions about what strength of evidence of treatment efficacy and harm is necessary to change practice and questions about how best to disseminate and implement the evidence. It seems that a systematic search of the evidence, applying rules of critical appraisal, qualitatively synthesising the evidence and publishing the results in a peer-reviewed journal [3] is not good enough. We have asked ourselves what else could we have done to get the message through? In the meantime we stay with the pragmatic conclusion of our systematic review on the efficacy of nonsteroidal anti-inflammatory drugs given by different routes: ‘If the patient can swallow, give the drug by mouth!’ M. R. Tramèr Division d’Anesthésiologie, Département APSIC, Hôpital Cantonal Universitaire, CH-1211 Genève, Switzerland