Analgesic effects of dexamethasone in burn injury.
OBJECTIVE
Glucocorticoids are well-known adjuvant analgesics in certain chronic pain states. There is, however, a paucity of data on their analgesic efficacy in acute pain. Therefore, the aim of the study was to examine the analgesic effects of dexamethasone in a validated burn model of acute inflammatory pain in humans.


METHODS
Twenty-two volunteers were investigated in a double-blind, randomized, placebo-controlled cross-over study. Intravenous dexamethasone 8 mg or placebo was administered on 2 separate study days. Two hours after drug administration, a first-degree burn injury was produced on the medial aspect of the nondominant calf (12.5 cm2, 47 degrees C for 7 minutes). Quantitative sensory testing included pain ratings to thermal and mechanical stimuli (visual analog scale [VAS]), assessments of thermal and mechanical detection thresholds, and areas of allodynia and secondary hyperalgesia.


RESULTS
The burn injury induced significant increases in erythema (P <.0001) and hyperalgesia (P <.001) in both groups. Pain ratings and development of tactile allodynia during the burn did not differ between dexamethasone and placebo treatments (P >.6). There were no significant differences between treatments in regard to skin erythema (P >.8), thermal or mechanical thresholds (P >.2), thermal or mechanical pain response (P >.2), or mechanical secondary hyperalgesia (P >.2). Dexamethasone had no analgesic effects in normal skin.


CONCLUSIONS
The study indicates that systemic administration of dexamethasone 2 hours before a burn injury does not reduce the inflammatory-mediated changes in quantitative sensory thresholds, pain perception, or skin erythema in humans.
Werner
Mads U
MU
Acute Pain Service, Department of Anesthesiology, Hvidovre University Hospital, Copenhagen, Denmark. madswerner@medscape.com
Lassen
Birgit
B
Kehlet
Henrik
H
D000328:Adult; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D002056:Burns / Q000150:complications*; D018592:Cross-Over Studies; D003907:Dexamethasone / Q000627:therapeutic use*; D004311:Double-Blind Method; D004890:Erythema / Q000188:drug therapy / Q000473:pathology; D006801:Humans; D006930:Hyperalgesia / Q000188:drug therapy / Q000209:etiology; D008297:Male; D010146:Pain / Q000188:drug therapy* / Q000209:etiology*; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects; D010812:Physical Stimulation; D012867:Skin / Q000294:innervation / Q000473:pathology; D013997:Time Factors
D000893:Anti-Inflammatory Agents; D003907:Dexamethasone