title: Antihypernociceptive synergy between ibuprofen, paracetamol and codeine in rats.
abstract: We investigated the effects of intraperitoneal injections of a combination of two cyclo-oxygenase inhibitors, ibuprofen and paracetamol, with a weak opiate, codeine, on nociception in Sprague Dawley rats. Administration of paracetamol (11, 44, and 88 mg/kg), ibuprofen (8.75, 35, and 140 mg/kg) or codeine (0.44, 1.75, and 3.5mg/kg) alone caused a dose-dependent inhibition of reperfusion hypernociception. Administration of a combination of 0.44 mg/kg codeine+8.75 mg/kg ibuprofen+11 mg/kg paracetamol, drug doses that did not significantly reduce reperfusion hypernociception when administered individually or in pairs, abolished reperfusion hypernociception, such that the antihypernociceptive efficacy of the combination was approximately 2.5-fold greater than that of the sum of the antihypernociceptive efficacy of the individual drugs. Coordinated motor function, tested using a rotarod, was not impaired at the doses we used. Thus, we have demonstrated that codeine, paracetamol and ibuprofen act synergistically to induce antihypernociception in rats at doses which do not affect motor function.
authors.affiliation: Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, South Africa.
authors.forename: Duncan
authors.initials: D
authors.lastname: Mitchell
authors.forename: Linda
authors.initials: L
authors.lastname: Gelgor
authors.forename: Juliane
authors.initials: J
authors.lastname: Weber
authors.forename: Peter R
authors.initials: PR
authors.lastname: Kamerman
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D003061:Codeine / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D004338:Drug Combinations; D004357:Drug Synergism; D007052:Ibuprofen / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D007511:Ischemia / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D045442:Rotarod Performance Test; D013696:Temperature
chemical_list: D000700:Analgesics; D004338:Drug Combinations; D000082:Acetaminophen; D003061:Codeine; D007052:Ibuprofen