title: Intravenous magnesium for chronic complex regional pain syndrome type 1 (CRPS-1).
abstract: OBJECTIVE
  To assess the effects of intravenous administration of magnesium on complex regional pain syndrome type 1 (CRPS-1), a randomized double-blind placebo-controlled trial was performed.
  
  
  METHODS
  Fifty-six patients with CRPS-1 (International Association for the Study of Pain Orlando criteria) received MgSO(4) 70 mg/kg or placebo (NaCl 0.9%) in 4 hours over 5 consecutive days. Pain (BOX-11 and McGill), the level of impairment (Impairment level Sum Score [ISS]), functional limitations (Radboud Skills Questionnaire, Walking Skills Questionnaire/questionnaire rising and sitting down), participation (Impact on Participation and Autonomy [IPA]), and quality of life (Short Form-36, EuroQol, IPA) were evaluated at baseline and at 1, 3, 6, and 12 weeks.
  
  
  RESULTS
  No significant differences were found between MgSO(4) and placebo on the BOX-11 and ISS at different time points during the trial on intention-to-treat and per-protocol analysis. A significant improvement on the BOX-11 was found after the first week of the trial in both groups (mean 0.7; standard deviation 1.1). For the MgSO(4) group, a clinically relevant and statistically significant improvement on the ISS at 1 week (median 5, interquartile range [IQR] -1 to 8) and a significant improvement on the McGill up to 6 weeks (median 2 words, IQR 0-4.5) were found compared with baseline, which were not found in the placebo group. Significant improvement in perceived job participation was found for the MgSO(4) group at 12 weeks (median improvement 1.44-1.17; P = 0.01). ISS improved significantly more in patients with a low Hospital Anxiety and Depression Scale (HADS) score (≤10) in the MgSO(4) group (mean 4.4 vs mean -3.1; P = 0.02).
  
  
  CONCLUSIONS
  Administration of the physiological competitive N-methyl-D-aspartate receptor antagonist magnesium in chronic CRPS provides insufficient benefit over placebo. Future research should focus on patients with acute CRPS and early signs and symptoms of central sensitization.
authors.affiliation: Department of Anesthesiology, VU University Medical Center, Amsterdam, The Netherlands; EMGO Institute for Health and Care Research (EMGO+), Amsterdam, The Netherlands; Knowledge Consortium Trauma Related Neural Dysfunction (TREND), Leiden, The Netherlands.
authors.forename: Sigrid G L
authors.initials: SG
authors.lastname: Fischer
authors.forename: Susan
authors.initials: S
authors.lastname: Collins
authors.forename: Sabine
authors.initials: S
authors.lastname: Boogaard
authors.forename: Stephan A
authors.initials: SA
authors.lastname: Loer
authors.forename: Wouter W A
authors.initials: WW
authors.lastname: Zuurmond
authors.forename: Roberto S G M
authors.initials: RS
authors.lastname: Perez
mesh_terms: D000328:Adult; D000700:Analgesics / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008278:Magnesium Sulfate / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D017288:Pain Threshold / Q000187:drug effects*; D011788:Quality of Life; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D012019:Reflex Sympathetic Dystrophy / Q000188:drug therapy*
chemical_list: D000700:Analgesics; D016194:Receptors, N-Methyl-D-Aspartate; D008278:Magnesium Sulfate
keywords: CRPS-1; Central Sensitization; Magnesium; NMDA Receptor