title: Ultra low-dose naloxone and tramadol/acetaminophen in elderly patients undergoing joint replacement surgery: a pilot study.
abstract: OBJECTIVE
  A pilot study was conducted to assess whether both the rationale and feasibility exist for future randomized clinical trials to evaluate the combined use of naloxone infusion and tramadol/acetaminophen as opioid-sparing drugs in elderly patients undergoing lower extremity joint replacement surgery.
  
  
  METHODS
  Ten patients 70 years of age or older undergoing either total knee (n=7) or total hip (n=3) arthroplasty were treated prospectively. Each patient received two tablets of tramadol/acetaminophen (Tramacet; Janssen-Ortho Inc, Canada) preoperatively and every 6 h postoperatively, as well as a naloxone infusion started preoperatively at 0.25 microg/kg/h and continued up to 48 h postoperatively. In addition, standard intraoperative care was provided with 0.2 mg of intrathecal morphine, 1.4 mL of 0.75% bupivacaine, and an intra-articular infiltration of 100 mL of 0.3% ropivacaine and 30 mg of ketorolac, as well as standard postoperative morphine via patient-controlled analgesia orders and celecoxib 200 mg twice daily for five days.
  
  
  METHODS
  Compared with seven historical controls, also 70 years of age or older, who had undergone either a total knee (n=4) or total hip (n=3) arthroplasty, postoperative opioid use was reduced by 80%. Except for transient nausea and vomiting in 40% and 20% of patients, respectively, the 10 patients on tramadol/acetaminophen and naloxone tolerated the new regimen without difficulty.
  
  
  CONCLUSIONS
  Consequently, a randomized, double-blinded clinical trial comparing standard therapy versus standard therapy plus these two drugs seems warranted. In such a trial, it would require approximately 20 subjects per treatment arm to detect a 80% decrease in morphine use.
authors.affiliation: Department of Anesthesia & Perioperative Medicine, University of Western Ontario, St Joseph's Health Care, London, Ontario, Canada. Ngozi.Imasogie@sjhc.london.on.ca
authors.forename: Ngozi N
authors.initials: NN
authors.lastname: Imasogie
authors.forename: Sudha
authors.initials: S
authors.lastname: Singh
authors.forename: James T
authors.initials: JT
authors.lastname: Watson
authors.forename: Debbie
authors.initials: D
authors.lastname: Hurley
authors.forename: Patricia
authors.initials: P
authors.lastname: Morley-Forster
mesh_terms: D000082:Acetaminophen / Q000627:therapeutic use*; D000368:Aged; D000369:Aged, 80 and over; D016058:Analgesia, Patient-Controlled / Q000379:methods*; D000700:Analgesics / Q000627:therapeutic use*; D019643:Arthroplasty, Replacement / Q000379:methods*; D006801:Humans; D035002:Lower Extremity / Q000601:surgery*; D010865:Pilot Projects; D011446:Prospective Studies; D014147:Tramadol / Q000627:therapeutic use*
chemical_list: D000700:Analgesics; D000082:Acetaminophen; D014147:Tramadol