title: Effects of gabapentin on experimental somatic pain and temporal summation.
abstract: OBJECTIVE
  Gabapentin is used for treatment of neuropathic pain, but its effect on different somatic pain modalities and integrative mechanisms are not completely understood. The aim of this double-blind, placebo-controlled experimental pain study, conducted on 20 healthy volunteers, was to examine the effect of a single dose of 1200 mg gabapentin on multi-modal experimental cutaneous and muscle pain models.
  
  
  METHODS
  The following pain models were applied: (1) pain thresholds to single and repeated cutaneous and intramuscular electrical stimulation (temporal summation to 5 stimuli delivered at 2 Hz); (2) stimulus-response function relating pain intensity scores (visual analog scale, VAS) to increasing current intensities for electrical skin and muscle stimuli (single and repeated, determined at baseline); and (3) the pain intensity (VAS) and pain areas after intramuscular injection of hypertonic saline. Pain assessments were performed prior to, and at 4, 6, and 8 hours after medication.
  
  
  RESULTS
  When responses were averaged across the post-dose times, gabapentin: (1) significantly increased the temporal summation pain threshold in skin compared with placebo (P = .03); (2) significantly reduced the area under the pain intensity curve to hypertonic saline injections in the muscle (P = .02); and (3) significantly reduced the area of pain evoked by hypertonic saline (P = .03).
  
  
  CONCLUSIONS
  Gabapentin reduces temporal summation of skin stimuli at pain threshold intensities; this may have potential as a biomarker for drugs with efficacy on neurogenic pain. The data also suggest that tonic muscle pain is responsive to gabapentin treatment and suggest further clinical studies.
authors.affiliation: Center for Sensory-Motor Interactions, Department of Health Science and Technology, Aalborg University, Denmark. LAN@hst.aau.dk
authors.forename: Lars
authors.initials: L
authors.lastname: Arendt-Nielsen
authors.forename: Jens Brøndum
authors.initials: JB
authors.lastname: Frøkjaer
authors.forename: Camilla
authors.initials: C
authors.lastname: Staahl
authors.forename: Thomas
authors.initials: T
authors.lastname: Graven-Nielsen
authors.forename: John P
authors.initials: JP
authors.lastname: Huggins
authors.forename: Trevor S
authors.initials: TS
authors.lastname: Smart
authors.forename: Asbjørn Mohr
authors.initials: AM
authors.lastname: Drewes
mesh_terms: D000328:Adult; D000588:Amines / Q000493:pharmacokinetics / Q000627:therapeutic use*; D000700:Analgesics / Q000493:pharmacokinetics / Q000627:therapeutic use*; D018592:Cross-Over Studies; D003509:Cyclohexanecarboxylic Acids / Q000493:pharmacokinetics / Q000627:therapeutic use*; D004311:Double-Blind Method; D004558:Electric Stimulation; D000077206:Gabapentin; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology; D009619:Nociceptors / Q000187:drug effects; D010146:Pain / Q000139:chemically induced / Q000188:drug therapy* / Q000523:psychology; D010147:Pain Measurement / Q000187:drug effects; D017288:Pain Threshold / Q000187:drug effects; D012867:Skin / Q000473:pathology; D005680:gamma-Aminobutyric Acid / Q000493:pharmacokinetics / Q000627:therapeutic use*
chemical_list: D000588:Amines; D000700:Analgesics; D003509:Cyclohexanecarboxylic Acids; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin