title: Peri-operative intravenous administration of magnesium sulphate and postoperative pain: a meta-analysis.
abstract: Intravenous magnesium has been reported to improve postoperative pain; however, the evidence is inconsistent. The objective of this quantitative systematic review is to evaluate whether or not the peri-operative administration of intravenous magnesium can reduce postoperative pain. Twenty-five trials comparing magnesium with placebo were identified. Independent of the mode of administration (bolus or continuous infusion), peri-operative magnesium reduced cumulative intravenous morphine consumption by 24.4% (mean difference: 7.6 mg, 95% CI -9.5 to -5.8 mg; p < 0.00001) at 24 h postoperatively. Numeric pain scores at rest and on movement at 24 h postoperatively were reduced by 4.2 (95% CI -6.3 to -2.1; p < 0.0001) and 9.2 (95% CI -16.1 to -2.3; p = 0.009) out of 100, respectively. We conclude that peri-operative intravenous magnesium reduces opioid consumption, and to a lesser extent, pain scores, in the first 24 h postoperatively, without any reported serious adverse effects.
authors.affiliation: Department of Anaesthesia, Toronto Western Hospital, University of Toronto, Toronto, Canada. eric.albrecht74@gmail.com 
authors.forename: E
authors.initials: E
authors.lastname: Albrecht
authors.forename: K R
authors.initials: KR
authors.lastname: Kirkham
authors.forename: S S
authors.initials: SS
authors.lastname: Liu
authors.forename: R
authors.initials: R
authors.lastname: Brull
mesh_terms: D059787:Acute Pain / Q000517:prevention & control; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use; D001919:Bradycardia / Q000139:chemically induced / Q000453:epidemiology; D023381:Endpoint Determination; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D008278:Magnesium Sulfate / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000627:therapeutic use; D010147:Pain Measurement / Q000187:drug effects; D010149:Postoperative Pain / Q000517:prevention & control*; D019990:Perioperative Care; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome
chemical_list: D000701:Analgesics, Opioid; D008278:Magnesium Sulfate; D009020:Morphine