title: Magnesium sulfate with lidocaine for preventing propofol injection pain: a randomized, double-blind, placebo-controlled trial.
abstract: OBJECTIVE
  Propofol injection pain, despite various strategies, remains common and troublesome. This study aimed to test the hypothesis that pretreatment with the combination of intravenous lidocaine and magnesium would have an additive effect on reducing propofol injection pain.
  
  
  METHODS
  After institutional review board (IRB) approval and informed consent, we performed a prospective, double-blind, placebo-controlled, randomized trial. Subjects were randomly assigned to pretreatment with either lidocaine (50 mg), magnesium sulfate (0.25 mg), lidocaine (50 mg) plus magnesium sulfate (0.25 mg), or 0.9 % sodium chloride. Following pretreatment, propofol (50 mg) was administered, and subjects were questioned regarding injection site pain and observed for behavioral signs of pain.
  
  
  RESULTS
  Two hundred subjects were enrolled and 158 subjects (39 placebo, 38 lidocaine, 44 magnesium sulfate, and 37 lidocaine plus magnesium sulfate) received their assigned pretreatment intervention. Intergroup baseline characteristics were similar. The proportion of subjects reporting propofol injection pain was highest in those pretreated with magnesium sulfate (57 %), followed by those pretreated with placebo (46 %), lidocaine plus magnesium sulfate (41 %), and then lidocaine (29 %; p = 0.011). When adjusted for age, gender, diabetes mellitus, chronic pain, tobacco use, and selective-serotonin reuptake inhibitor use, the pain response scale scores were significantly reduced by lidocaine pretreatment compared to magnesium sulfate and placebo (p = 0.031 and p = 0.0003, respectively).
  
  
  CONCLUSIONS
  In this double-blind, placebo-controlled, randomized trial, the combination of intravenous magnesium sulfate and lidocaine offered no additional benefit for the relief of propofol injection pain compared to intravenous lidocaine alone. An improved, receptor-based understanding of the mechanism of propofol injection pain is still needed.
authors.affiliation: Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, B6/319, Madison, WI, 53792-3272, USA, galgon@wisc.edu.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Galgon
authors.forename: Peter
authors.initials: P
authors.lastname: Strube
authors.forename: Jake
authors.initials: J
authors.lastname: Heier
authors.forename: Jeremy
authors.initials: J
authors.lastname: Groth
authors.forename: Sijian
authors.initials: S
authors.lastname: Wang
authors.forename: Kristopher M
authors.initials: KM
authors.lastname: Schroeder
mesh_terms: D000328:Adult; D000771:Anesthesia, Intravenous / Q000009:adverse effects*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000009:adverse effects*; D000779:Anesthetics, Local / Q000627:therapeutic use*; D004311:Double-Blind Method; D004338:Drug Combinations; D005260:Female; D006801:Humans; D007275:Injections, Intravenous / Q000009:adverse effects*; D008012:Lidocaine / Q000627:therapeutic use*; D008278:Magnesium Sulfate / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology* / Q000517:prevention & control*; D010147:Pain Measurement / Q000187:drug effects; D015742:Propofol / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D004338:Drug Combinations; D008278:Magnesium Sulfate; D008012:Lidocaine; D015742:Propofol
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