title: The analgesic efficacy of tramadol is impaired by concurrent administration of ondansetron.
abstract: Tramadol has weak opioid properties, and an analgesic effect that is mediated mainly by inhibition of the reuptake of norepinephrine and serotonin (5-hydroxytryptamine [5-HT]) and facilitation of 5-HT release (1,2) at the spinal cord. Because 5-HT3 receptors play a key role in pain transmission at the spinal level (3), the 5-HT3 antagonist ondansetron may decrease the efficacy of tramadol, as suggested in an abstract by Maroof et al. In that study, a small dose of 1 mg/kg tramadol was administered along with ondansetron 0.1 mg/kg or placebo, 15 min before the induction of anesthesia. Early postoperative pain scored differed significantly between the test groups. We therefore tested the hypothesis that the tramadol requirement by patient-controlled analgesia (PCA) may be increased when ondansetron is administered for antiemetic prophylaxis.
authors.affiliation: Department of Anesthesia and Intensive Care, OLV-Hospital, Aalst, Belgium. jan.de.witte@olvz-aalst.be
authors.forename: J L
authors.initials: JL
authors.lastname: De Witte
authors.forename: B
authors.initials: B
authors.lastname: Schoenmaekers
authors.forename: D I
authors.initials: DI
authors.lastname: Sessler
authors.forename: T
authors.initials: T
authors.lastname: Deloof
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid / Q000008:administration & dosage*; D000932:Antiemetics / Q000008:administration & dosage*; D004347:Drug Interactions; D005260:Female; D006801:Humans; D007796:Laminectomy; D008297:Male; D008875:Middle Aged; D017294:Ondansetron / Q000008:administration & dosage*; D010147:Pain Measurement; D010149:Postoperative Pain / Q000188:drug therapy / Q000517:prevention & control*; D020250:Postoperative Nausea and Vomiting / Q000517:prevention & control; D014147:Tramadol / Q000008:administration & dosage*
chemical_list: D000701:Analgesics, Opioid; D000932:Antiemetics; D014147:Tramadol; D017294:Ondansetron