title: What epidural opioid results in the best analgesia outcomes and fewest side effects after surgery?: a meta-analysis of randomized controlled trials.
abstract: BACKGROUND
  Epidural opioids are widely used for central neuraxial blockade and postoperative analgesia. However, differences in analgesic efficacy and side effect rates among individual opioids remain controversial.
  
  
  METHODS
  We conducted a random-effects meta-analysis of randomized controlled trials that compared at least 2 continuous epidural infusions for acute postoperative analgesia over at least 24 hours. Individual study data were weighted by the inverse-variance method. Visual analog scale (VAS) pain scores were the primary outcome. Secondary outcomes included opioid side effects, such as pruritus, postoperative nausea and vomiting (PONV), sedation, hypotension, and respiratory depression.
  
  
  RESULTS
  Nineteen of the 24 trials included compared 2 of the following opioids: morphine, fentanyl, or sufentanil. The total subjects studied were 1513. Pooled analysis by type of surgery showed no clinically significant differences in VAS pain scores at any time after surgery. There were more PONV (OR = 1.91; 95% CI, 1.14-3.18; P = 0.014) and perhaps pruritus (OR = 1.64; 95% CI, 0.98-2.76; P = 0.162) with morphine compared to fentanyl. Total opioid consumption differed only in the trials comparing morphine and fentanyl, where patients in the morphine group required 1.2 mg (of morphine equivalent) less (95% CI, 0.27-2.18). Use of analgesic adjuncts was similar for all but 2 studies.
  
  
  CONCLUSIONS
  Analgesic outcome, in terms of VAS pain score, was similar between the epidural opioids studied. These similarities in analgesia may reflect the common practices of concurrently using epidural local anesthetics with the opioids and titrating infusion rates according to a patient's pain status. With respect to side effects, the incidence of PONV and possibly pruritus was higher with morphine compared with fentanyl, despite there being similar total opioid consumption between those groups.
authors.affiliation: From the Department of Anesthesia, McMaster University, Hamilton, Ontario; Department of Anesthesia, University of Toronto, Toronto, Ontario; Michael G. School of Medicine, McMaster University, Hamilton, Ontario; Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario; and Biostatistics Unit, St. Joseph's Healthcare Hamilton, Hamilton, Ontario.
authors.forename: Nayer
authors.initials: N
authors.lastname: Youssef
authors.forename: David
authors.initials: D
authors.lastname: Orlov
authors.forename: Tristan
authors.initials: T
authors.lastname: Alie
authors.forename: Matthew
authors.initials: M
authors.lastname: Chong
authors.forename: Ji
authors.initials: J
authors.lastname: Cheng
authors.forename: Lehana
authors.initials: L
authors.lastname: Thabane
authors.forename: James
authors.initials: J
authors.lastname: Paul
mesh_terms: D015360:Analgesia, Epidural / Q000009:adverse effects / Q000379:methods*; D000701:Analgesics, Opioid / Q000008:administration & dosage*; D006801:Humans; D059408:Pain Management / Q000379:methods; D010147:Pain Measurement / Q000187:drug effects / Q000379:methods; D010149:Postoperative Pain / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D016032:Randomized Controlled Trials as Topic / Q000379:methods; D016896:Treatment Outcome
chemical_list: D000701:Analgesics, Opioid