title: S-ketamine modulates hyperalgesia in patients with chronic pancreatitis pain.
abstract: OBJECTIVE
  Upper abdominal pain is a dominant feature of chronic pancreatitis. A key phenomenon in this context is hyperalgesia, typically associated with N-methyl-d-aspartate receptor activation. This exploratory study evaluates acute effects of S-ketamine, a noncompetitive N-methyl-d-aspartate antagonist, in modulating generalized hyperalgesia in chronic pancreatitis pain.
  
  
  METHODS
  In a blinded crossover trial, 10 chronic pancreatitis pain patients received S-ketamine for 3 hrs at 2 μg · kg · min or placebo infusion at an equivalent rate in randomized order. Clinical pain was assessed via visual analog scale (VAS) and short Dutch Language Version McGill Pain Questionnaire (sf-MPQ-DLV). Pressure pain thresholds (PPTs) were measured in dermatome C5, T4, dorsal T10, L1, and L4, and the sum of PPTs (SOPPT) calculated before, at end of, and after infusion.
  
  
  RESULTS
  Nine patients completed the study. Median pain VAS before infusion was 29 mm at rest, 32 mm during activity; sf-MPQ-DLV score was 4. For the S-ketamine session median SOPPT change at infusion end was significantly higher than in the placebo session (218; interquartile range [IQR], 116-527, versus -123 [IQR, -330 to 24]; P = 0.005) and significant versus preinfusion values (2109 [IQR, 964-3035] vs 1914 [IQR, 842-2884]; P = 0.03). The SOPPT was unchanged versus preinfusion values and similar between groups at 1 hr after infusion end. No significant changes in VAS and sf-MPQ-DLV occurred.
  
  
  CONCLUSIONS
  S-ketamine infusion is more effective than placebo in increasing PPTs in chronic pancreatitis pain patients immediately after infusion. This effect did not outlast the infusion. Further research is warranted into S-ketamine use for reducing generalized hyperalgesia and chronic pancreatitis pain.
authors.affiliation: Department of Surgery, Radboud University Nijmegen Medical Centre, The Netherlands.
authors.forename: Stefan A W
authors.initials: SA
authors.lastname: Bouwense
authors.forename: Hessel C J L
authors.initials: HC
authors.lastname: Buscher
authors.forename: Harry
authors.initials: H
authors.lastname: van Goor
authors.forename: Oliver H G
authors.initials: OH
authors.lastname: Wilder-Smith
mesh_terms: D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000150:complications / Q000188:drug therapy*; D007262:Infusions, Intravenous; D007649:Ketamine / Q000008:administration & dosage* / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000150:complications / Q000188:drug therapy*; D010147:Pain Measurement / Q000187:drug effects / Q000379:methods; D050500:Pancreatitis, Chronic / Q000150:complications / Q000188:drug therapy*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D013237:Stereoisomerism
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; D007649:Ketamine