Effects of intrathecal ketorolac on human experimental pain.
BACKGROUND
Nonsteroidal antiinflammatory drugs, the most commonly used analgesics, reduce pain not only by inhibiting cyclooxygenase at peripheral sites of inflammation but also by potentially inhibiting cyclooxygenase in the central nervous system, especially the spinal cord. Animal studies suggest that products of cyclooxygenase in the spinal cord do not alter pain responses to acute noxious stimuli but reduce pain and sensitization after peripheral inflammation. We used a spinal injection of small doses of the cyclooxygenase inhibitor ketorolac to survey the role of spinal cyclooxygenase in human experimental pain and hypersensitivity states.


METHODS
After regulatory agency approval and informed consent, we examined the effect of 2.0 mg intrathecal ketorolac in 41 healthy volunteers to acute noxious thermal stimuli in normal skin and to mechanical stimuli in skin sensitized by topical capsaicin or ultraviolet burn. We also examined the effect of intravenous ketorolac.


RESULTS
Intrathecal ketorolac reduced hypersensitivity when it was induced by a combination of ultraviolet burn plus intermittent heat and, according to one of the two analytical strategies, when it was induced by ultraviolet burn alone.


CONCLUSIONS
These data suggest a more limited role for spinal cord cyclooxygenase in human pain states than predicted by studies in animals.
Eisenach
James C
JC
Department of Anesthesiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1009, USA. eisenach@wfubmc.edu
Curry
Regina
R
Tong
Chuanyao
C
Houle
Timothy T
TT
Yaksh
Tony L
TL
D000293:Adolescent; D000328:Adult; D002211:Capsaicin / Q000633:toxicity; D005260:Female; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D007278:Injections, Spinal; D020910:Ketorolac / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000139:chemically induced / Q000188:drug therapy* / Q000209:etiology; D010147:Pain Measurement / Q000187:drug effects* / Q000379:methods; D010812:Physical Stimulation / Q000009:adverse effects; D014466:Ultraviolet Rays / Q000009:adverse effects; D055815:Young Adult
D002211:Capsaicin; D020910:Ketorolac
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