title: Synergistic interaction between dexamethasone and tramadol in a murine model of acute visceral pain.
abstract: Tramadol is effective in the management of mild to moderate postoperative pain, but its administration is associated with nausea and vomiting. Patients treated with tramadol, often receive dexamethasone as antiemetic. The aim of our investigation was to assess if the two drugs interact in a murine model of acute visceral pain. Using the acetic acid writhing test in mice, we assessed the antinociceptive effects of tramadol and dexamethasone (a glucocorticoid with antiemetic effect) administrated individually and in a 1 : 1 fixed ratio combination. Tramadol and dexamethasone induced a dose-dependent inhibition of the writhing response when administered individually, with ED(50) values of 2.9 [2.09-4.31, 95% confidence limit (CL)] mg/kg, and 0.13 (0.05-0.29, 95% CL) mg/kg, respectively. The ED(50) of the combination was 0.13 (0.01-0.29, 95% CL) mg/kg; the isobolographic and interaction index analysis revealed a synergistic interaction. The results suggest that the combination of tramadol and dexamethasone could be beneficial in the management of postoperative pain in humans.
authors.affiliation: Department of Anaesthesiology, Hospital Universitario del Mar, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Christian
authors.initials: C
authors.lastname: Dürsteler
authors.forename: Hugo F
authors.initials: HF
authors.lastname: Miranda
authors.forename: Raquel
authors.initials: R
authors.lastname: Poveda
authors.forename: Anna
authors.initials: A
authors.lastname: Mases
authors.forename: Eulalia
authors.initials: E
authors.lastname: Planas
authors.forename: Margarita M
authors.initials: MM
authors.lastname: Puig
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D000932:Antiemetics / Q000008:administration & dosage / Q000494:pharmacology*; D003907:Dexamethasone / Q000008:administration & dosage / Q000494:pharmacology*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage / Q000494:pharmacology; D006801:Humans; D051379:Mice; D008954:Models, Biological; D010146:Pain / Q000188:drug therapy*; D010147:Pain Measurement; D014147:Tramadol / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000701:Analgesics, Opioid; D000932:Antiemetics; D005938:Glucocorticoids; D014147:Tramadol; D003907:Dexamethasone