title: Short-term treatment with parecoxib for complex regional pain syndrome: a randomized, placebo-controlled double-blind trial.
abstract: BACKGROUND
  Complex regional pain syndrome (CRPS) is characterized by signs and symptoms of peripheral inflammation, which leads to peripheral neural sensitization associated most frequently (in about 70%) with blunt pressure hyperalgesia. Therefore, we hypothesized that treatment of CRPS patients with a selective COX-2-inhibitor would alleviate the abnormally low pressure pain threshold (PPT) and reduce pain intensity and edema.
  
  
  METHODS
  Twenty patients with CRPS type I (n = 16) and II of the upper limb and abnormally low PPT were double-blind randomised into 2 groups of 10 patients each to receive a 2-day intravenous treatment of either 80 mg parecoxib per day (group I) or placebo (NaCl 0.9%, group II). Standardized quantitative sensory testing (QST) using the DFNS protocol was performed before and after treatment. Pain intensity (NRS 0 - 10); circumferences of the fingers II, IV, and V (mm); PPT (kPa, thenar/hypothenar); and adverse events were recorded daily.
  
  
  METHODS
  Wilcoxon-test, Mann-Whitney-U-test, Friedman-test, Fisher-test, significance level: P < 0.05.
  
  
  METHODS
  Proof of concept trial performed in randomized, placebo-controlled, double blind style .
  
  
  METHODS
  Pain Management Center in Germany.
  
  
  RESULTS
  There were no group differences in PTT or other QST parameters. After treatment, PPT decreased insignificantly in group I (median [range]; before: 224.0 [121.0 - 52937] kPa, afterwards: 186.4 [101.4 - 526.5] kPa) and increased insignificantly in group II (before: 207.6 [170.0 - 320.5] kPa; afterwards: 235.4 [163.5 - 349.9] kPa). Pain scores and finger circumferences remained unchanged in both groups.
  
  
  CONCLUSIONS
  Due to difficulty in recruitment the trial was closed after inclusion of 20 patients.
  
  
  CONCLUSIONS
  In the present proof-of-concept trial, short-term treatment with the selective COX-2-inhibitor parecoxib influenced neither PPT nor edema or pain. COX-2 might be less important than previously assumed. However, the results are limited due to the small number of patients, short-term treatment, and focus on the PPT, which could have led to false negative results of the present study and covered the expected therapeutic effect.
authors.affiliation: Department of Pain Medicine, Berufsgenossenschaftliches Universitatsklinikum Bergmannsheil GmbH Bochum, Ruhr University Bochum, Germany.
authors.forename: Anna J
authors.initials: AJ
authors.lastname: Breuer
authors.forename: Tina
authors.initials: T
authors.lastname: Mainka
authors.forename: Nora
authors.initials: N
authors.lastname: Hansel
authors.forename: Christoph
authors.initials: C
authors.lastname: Maier
authors.forename: Elena K
authors.initials: EK
authors.lastname: Krumova
mesh_terms: D000328:Adult; D000368:Aged; D020918:Complex Regional Pain Syndromes / Q000145:classification / Q000188:drug therapy* / Q000523:psychology; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D004311:Double-Blind Method; D004487:Edema / Q000188:drug therapy; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000188:drug therapy / Q000503:physiopathology; D007555:Isoxazoles / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D012684:Sensory Thresholds / Q000187:drug effects; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D007555:Isoxazoles; C409945:parecoxib