title: Antihyperalgesic efficacy of 5% lidocaine medicated plaster in capsaicin and sunburn pain models--two randomized, double-blinded, placebo-controlled crossover trials in healthy volunteers.
abstract: OBJECTIVE
  The aim of this research is to analyze analgesic efficacy of the 5% lidocaine medicated plaster in two randomized, double-blinded, placebo-controlled, crossover studies in 16 healthy volunteers using capsaicin and sunburn pain models.
  
  
  METHODS
  Lidocaine and placebo plasters were simultaneously applied to forearms and thighs at contralateral body sites for three alternating 12-h plaster-on/plaster-off periods. Between the second and third plaster-on period, 4.2-cm circular spots on both pretreated thighs were irradiated with three times the individual minimal erythema dose of UVB light. After the last plaster-on period, 20 μl of 0.1% capsaicin was injected intradermally into both forearms. The study was repeated using a single 12-h plaster application.
  
  
  RESULTS
  The area of pinprick hyperalgesia was diminished by 53% (p < 0.003) in the capsaicin model and by 84% (p < 0.0001) in the sunburn model; the intensity of mechanical hyperalgesia to rigid filaments (8 - 512 mN) was reduced in both models. Cold pain perception threshold was reduced (19.7°C ± 8.0 vs 21.8°C ± 6.8 for placebo, p < 0.05, sunburn). Similar effects were observed in the 12-h exposure study. No effect was seen on capsaicin-induced spontaneous pain and flare size, or blood flow in the sunburn area, and heat hyperalgesia in either study.
  
  
  CONCLUSIONS
  Lidocaine plaster effectively treats mechanical hyperalgesia and cold pain.
authors.affiliation: Medical University of Vienna, Department of Anesthesia, Intensive Care Medicine and Pain Therapy, Vienna Human Pain Research Group, Wilhelminenspital, Montleartstrasse 37, A-1160 Vienna, Austria. burkhard.gustorff@meduniwien.ac.at
authors.forename: Burkhard
authors.initials: B
authors.lastname: Gustorff
authors.forename: David
authors.initials: D
authors.lastname: Hauer
authors.forename: Johannes
authors.initials: J
authors.lastname: Thaler
authors.forename: Astrid
authors.initials: A
authors.lastname: Seis
authors.forename: Julia
authors.initials: J
authors.lastname: Draxler
mesh_terms: D000279:Administration, Cutaneous; D000328:Adult; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000627:therapeutic use*; D002211:Capsaicin / Q000008:administration & dosage / Q000494:pharmacology*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D006801:Humans; D006930:Hyperalgesia / Q000139:chemically induced / Q000517:prevention & control*; D008012:Lidocaine / Q000008:administration & dosage / Q000627:therapeutic use*; D009437:Neuralgia / Q000139:chemically induced / Q000517:prevention & control*; D010147:Pain Measurement; D010812:Physical Stimulation; D013471:Sunburn / Q000150:complications*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine; D002211:Capsaicin