Codeine did not increase analgesic efficacy of coxibs in contrast to that of paracetamol or ibuprofen: isobolographic analysis in mice.

Abstract

There is good evidence that opioids can potentiate analgesic activity of some older non-opioid analgesics (such as paracetamol or ibuprofen) but it is not known whether this also holds true for newer non-opioid analgesics that selectively inhibit cyclooxygenase 2 (coxibs). This study was undertaken to determine the nature of the interaction between codeine and celecoxib or etoricoxib in peritoneal irritation-induced visceral pain in mice. For comparison, interactions of codeine with paracetamol and ibuprofen were also tested using the same method.