title: Differential effects of a 5% lidocaine medicated patch in peripheral nerve injury.
abstract: BACKGROUND
  We examined the effect of topical lidocaine on the function of small and large fibers in patients with peripheral neuropathic pain due to traumatic or postoperative nerve injury.
  
  
  METHODS
  In an open-label study, 24 patients were treated with a 5% lidocaine patch for up to 12 weeks. We recorded contact heat evoked potentials (CHEPs) and performed quantitative sensory testing (QST) before and after treatment with the contralateral side as control.
  
  
  RESULTS
  Twenty-one patients (mean age 47.6 ± 13.5 years) completed the study. Lidocaine increased cold pain threshold (P = 0.04) and reduced CHEP amplitude (P = 0.007) with no effect on other QST parameters. Patients responding to treatment had less cold detection deficit on the affected side and had a larger increase in cold pain detection threshold following treatment than nonresponders.
  
  
  CONCLUSIONS
  Controlled trials are warranted to further understand the mechanisms mediating the effects of topical lidocaine.
authors: Danish Pain Research Center, Aarhus University Hospital, Norrebrogade 44, Building 1A, DK-8000, Aarhus C, Denmark. caspar.madsen@ki.au.dk
authors: Caspar S
authors: CS
authors: Madsen
authors: Birger
authors: B
authors: Johnsen
authors: Anders
authors: A
authors: Fuglsang-Frederiksen
authors: Troels S
authors: TS
authors: Jensen
authors: Nanna B
authors: NB
authors: Finnerup
mesh_terms: D000328:Adult; D000779:Anesthetics, Local / Q000008:administration & dosage*; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000188:drug therapy / Q000209:etiology; D008012:Lidocaine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D059348:Peripheral Nerve Injuries / Q000150:complications / Q000188:drug therapy* / Q000209:etiology; D011183:Postoperative Complications / Q000503:physiopathology; D011930:Reaction Time / Q000187:drug effects; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires; D057968:Transdermal Patch; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine
keywords: contact heat evoked potentials (CHEPs); nerve injury; peripheral neuropathic pain; quantitative sensory testing (QST); topical lidocaine