title: The perioperative combination of methadone and ketamine reduces post-operative opioid usage compared with methadone alone.
abstract: BACKGROUND
  A synergy between ketamine and methadone (ME) to produce antinociception has been demonstrated in experimental neuropathy. We wanted to compare post-operative opioid requirements in patients undergoing multilevel lumbar arthrodesis after the administration combined ME-ketamine (MK) or ME alone.
  
  
  METHODS
  This was a randomised double-blind study. During sevoflurane-remifentanil anaesthesia, 11 patients in each group received the following: ketamine bolus (0.5 mg/kg) after tracheal intubation, followed by an infusion of 2.5 μg/kg/min in the MK or saline bolus plus infusion in the ME group. Post-operative analgesia - during 48 h - was provided by patient-controlled analgesia (PCA), delivering bolus containing the following: ME 0.25 mg plus ketamine 0.5 mg in the MK group or ME 0.5 mg in the ME group. Lockout was 10 min, maximum of 3 boluses/h in both groups. Before closing the wound, all the patients received intravenous (i.v.) ME 0.1 mg/kg, dexketoprophen and paracetamol. Pain intensity was evaluated by a numerical rating scale (NRS), on arrival at recovery room (RR) and 24 and 48 h after surgery. In the RR, i.v. ME was administered until NRS was 3 when PCA was started. Dexketoprophen and paracetamol were administered 48 h.
  
  
  RESULTS
  Remifentanil requirements were higher in the MK group (P = 0.004). Patients in the MK group received 70% less ME by PCA at 24 h (MK vs. ME group, median and interquartile range) - 3.43 mg (1.9-6.5) vs. 15 mg (9.65-17.38) (P < 0.001) - and at 48 h - 2 mg (0.5-3.63) vs. 9.5 mg (3.5-13.75) (P = 0.001). Patients in the MK group also attempted less doses, at 24 h: 19.5 (12.75-79.5) vs. 98 (41.5-137) (P = 0.043). Both groups had similar NRS values and comparable side effects.
  
  
  CONCLUSIONS
  Perioperative ketamine-ME combination significantly decreased opioid consumption by PCA.
authors: Department of Anaesthesiology, Parc de Salut Mar, Universitat Autónoma de Barcelona, Barcelona, Spain.
authors: S
authors: S
authors: Pacreu
authors: J
authors: J
authors: Fernández Candil
authors: L
authors: L
authors: Moltó
authors: J
authors: J
authors: Carazo
authors: S
authors: S
authors: Fernández Galinski
mesh_terms: D000328:Adult; D000368:Aged; D016058:Analgesia, Patient-Controlled; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use*; D000768:Anesthesia, General; D000778:Anesthetics, Dissociative / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007262:Infusions, Intravenous; D007649:Ketamine / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008691:Methadone / Q000008:administration & dosage / Q000627:therapeutic use*; D008875:Middle Aged; D010149:Postoperative Pain / Q000188:drug therapy* / Q000517:prevention & control*; D019990:Perioperative Care / Q000379:methods*; D010880:Piperidines / Q000008:administration & dosage / Q000627:therapeutic use; D000077208:Remifentanil; D013123:Spinal Fusion; D013131:Spine / Q000601:surgery
chemical_list: D000701:Analgesics, Opioid; D000778:Anesthetics, Dissociative; D010880:Piperidines; D007649:Ketamine; D000077208:Remifentanil; D008691:Methadone