Relief of post-herpetic neuralgia with the N-methyl-D-aspartic acid receptor antagonist ketamine: a double-blind, cross-over comparison with morphine and placebo.
Pain and sensory thresholds were examined before and after intravenous administration of ketamine (0.15 mg/kg), morphine (0.075 mg/kg) or saline in 8 patients with post-herpetic neuralgia. A randomized, double-blind, cross-over study design was used. Post-herpetic neuralgia was associated with impaired sensory function, as shown by reduced tactile and warm sensation in the affected compared with the contralateral non-affected skin area. Neither ketamine nor morphine changed significantly the thresholds for warm, cold, heat pain or tactile sensation. However, ketamine normalized abnormal heat pain sensations in 4 patients, probably due to a central effect. Ketamine, but not morphine, produced significant relief of pain. Pain evoked by non-noxious stimulation of the skin (allodynia) was significantly inhibited by ketamine as well as by morphine. Wind-up-like pain (i.e., pain evoked by repeatedly pricking the affected skin area) was significantly inhibited by ketamine, but significantly aggravated by morphine. Side effects were observed in all the 8 patients after injection of ketamine and in 6 patients after injection of morphine. The present results support the hypothesis that the N-methyl-D-aspartic acid (NMDA) receptors are involved in the control of post-herpetic neuralgia including allodynia and wind-up-like pain. The NMDA receptors also may play a role in the modulation of thermal perception.
Department of Neurosurgery, Ullevål Hospital, OsloNorway Department of Neurology, The National Hospital, University of Oslo, OsloNorway Departments of Anaesthesiology, The National Hospital, University of Oslo, OsloNorway.
Per Kristian
PK
Eide
Ellen
E
Jørum
Audun
A
Stubhaug
Jørn
J
Bremnes
Harald
H
Breivik
D000368:Aged; D000369:Aged, 80 and over; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006566:Herpesviridae Infections / Q000503:physiopathology*; D006358:Hot Temperature; D006801:Humans; D007649:Ketamine / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D009020:Morphine / Q000009:adverse effects / Q000627:therapeutic use*; D009437:Neuralgia / Q000188:drug therapy*; D010147:Pain Measurement / Q000187:drug effects; D017288:Pain Threshold / Q000187:drug effects; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*
D016194:Receptors, N-Methyl-D-Aspartate; D007649:Ketamine; D009020:Morphine