Abstract | BACKGROUND: OBJECTIVES: The aim of this study was to assess the effects of topically applied ketamine using the intradermal capsaicin model in healthy volunteers. METHODS: Nine healthy subjects received ketamine and placebo gel on 3 occasions in a randomized, double-blind, and crossover manner. The concentration of ketamine was 50 mg/mL. One milliliter of gel was rubbed into the skin of both forearms 10 minutes before the intradermal injection of capsaicin (250 microg). Thereafter, the intensity and unpleasantness of spontaneous and evoked pain and dysesthesia was assessed up to 60 minutes using a 10-cm visual analog scale. Pain and dysesthesia were evoked using cotton gauze, a von Frey microfilament, and 38 degrees C, 42 degrees C, and 47 degrees C heat. Side effects were recorded, and individuals' subjective experiences were assessed with a standard questionnaire. RESULTS: DISCUSSION: A significant reduction of mechanical hyperalgesia was produced by topically and pre-emptively applied ketamine in healthy patients. We propose that the mechanism of action would be the reduction of central sensitization caused by the absorption of ketamine in circulation.
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Authors | Reino Pöyhiä, Anneli Vainio |
Journal | The Clinical journal of pain
(Clin J Pain)
Vol. 22
Issue 1
Pg. 32-6
(Jan 2006)
ISSN: 0749-8047 [Print] United States |
PMID | 16340591
(Publication Type: Comparative Study, Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)
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Chemical References |
- Anesthetics, Dissociative
- Ketamine
- Capsaicin
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Topics |
- Administration, Topical
- Adult
- Analysis of Variance
- Anesthetics, Dissociative
(administration & dosage)
- Area Under Curve
- Capsaicin
- Cross-Over Studies
- Double-Blind Method
- Humans
- Hyperalgesia
(chemically induced, drug therapy)
- Ketamine
(administration & dosage)
- Male
- Middle Aged
- Pain Measurement
(methods)
- Time Factors
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