title: Effects of Systemic Magnesium on Post-operative Analgesia: Is the Current Evidence Strong Enough?
abstract: BACKGROUND
  Clinical studies have been previously carried out on the efficacy of systemic magnesium to minimize postoperative pain, however, with controversial results. A quantitative meta-analysis was performed to evaluate the analgesic efficacy and safety of systemic magnesium on post-operative pain.
  
  
  METHODS
  Comprehensive systematic review of all relevant, publsished randomized controlled trials.
  
  
  METHODS
  A search was conducted of published literature in MEDLINE, PsycINFO, Scopus, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases from inception to Sep-Oct 2014. Randomized controlled trials (RCTs) that compared magnesium with placebo were identified. Effects were summarized using standardized mean differences (SMDs), weighed mean differences (WMD), or odds ratio (OR) with suitable effect model.
  
  
  RESULTS
  Twenty-seven RCTs involving 1,504 patients were included. In total, peri-operative magnesium significantly reduced the pain score at rest (SMD, -1.43, 95% CI, -2.74 to -0.12, < 0.01). Magnesium significantly reduced analgesic consumption (SMD, -1.72, 95% CI, -3.21 to -0.23) in patients undergoing urogenital, orthopaedic, and cardiovascular surgeries, but was inconclusive for patients receiving gastrointestinal surgeries. The obvious analgesia of systemic magnesium was observed on reducing the pain score during movement at 24 hours after operation (SMD, -0.05, 95% CI, -0.43 to 0.32). Moreover, magnesium administration showed a beneficial effect with regard to intra-operative hemodynamics and reduced extubation time in the cardiovascular surgery patients (WMD, -29.34 min, 95% CI, -35.74 to -22.94, P < 0.01).
  
  
  CONCLUSIONS
  Focused only on the quality of analgesia on postoperative pain with regards to surgery type.
  
  
  CONCLUSIONS
  Our study suggests that systemic magnesium during general anesthesia significantly decreases post-operative pain scores without increasing adverse events. It should be noted that since there are 18 ongoing RCTs without published data, it is still premature to draw conclusions on the long-term analgesic effects of magnesium as well as potential gender or age difference.
authors.forename: Bao-Lin
authors.initials: BL
authors.lastname: Guo
authors.forename: Yan
authors.initials: Y
authors.lastname: Lin
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.affiliation: Department of Neurobiology and Collaborative Innovation Center for Brain Science, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Chen-Xi
authors.initials: CX
authors.lastname: Zhen
authors.affiliation: State Key Laboratory of Military Stomatology, College of Stomatology, Fourth Military Medical University.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Bao-Cheng
authors.forename: Huang-Hui
authors.initials: HH
authors.lastname: Wu
authors.forename: Alan David
authors.initials: AD
authors.lastname: Kaye
authors.affiliation: State Key Laboratory of Military Stomatology, College of Stomatology, Fourth Military Medical University, Xi'an.
authors.forename: Jian-Hong
authors.initials: JH
authors.lastname: Duan
authors.affiliation: Department of Neurosurgery, Tang'du Hospital, Fourth Military Medical University, Xi'an.
authors.forename: Yan
authors.initials: Y
authors.lastname: Qu
mesh_terms: D000700:Analgesics / Q000627:therapeutic use*; D000768:Anesthesia, General; D019317:Evidence-Based Medicine; D006801:Humans; D017616:Magnesium Compounds / Q000627:therapeutic use*; D010149:Postoperative Pain / Q000188:drug therapy*; D016032:Randomized Controlled Trials as Topic
chemical_list: D000700:Analgesics; D017616:Magnesium Compounds