Effects of Lidocaine Patch on Intradermal Capsaicin Induced Pain and Hyperalgesia
Information source: University of California, San Diego
Information obtained from ClinicalTrials.gov on June 20, 2008
Link to the current ClinicalTrials.gov record.
Condition(s) targeted: Pain; Hyperalgesia
Intervention: Lidoderm Patch (Drug)
Phase: Phase 1
Sponsored by: University of California, San Diego
Official(s) and/or principal investigator(s):
Mark S. Wallace, MD, Principal Investigator, Affiliation: University of California, San Diego
To determine the effects of Lidocaine patch on the pain and hyperalgesia induced by
Official title: Effects of Lidocaine Patch on Intradermal Capsaicin Induced Pain and Hyperalgesia
Study design: Treatment, Randomized, Double-Blind, Active Control, Single Group Assignment, Safety Study
Four neurosensory tests: warm and cold sensation,warm/cold pain/touch/mechanical pain.
Warm and cold sensation measured w/a Thermal Sensory
Touch will be measured using von Frey hairs. Calibrated von Frey hairs are filaments of varying size. The filament are selected at random and 3 successive stimuli are applied for 1.5 second at 5 second intervals per filament
Mechanical pain will be measured using von Frey hairs. Endpoint will be pain.
Allodynia and Hyperalgesia
At the completion of the stimulation, areas of cutaneous allodynia and hyperalgesia will be mapped. The region of hyperalgesia will be established with a 5.18 von Frey hair, and the area of allodynia with a foam brush gently stroked on the skin.
A randomized, double-blinded, placebo controlled methodology will be conducted. At the
session subjects will be exposed to placebo patch and lidocaine patch. Prior to study drug
administration, a baseline neurosensory test on the volar aspect of both forearms will be
performed and baseline vital signs will be measured. A placebo patch and a lidocaine patch
will then be applied to the volar aspect of each forearm. The arms will be randomized to
which arm receives placebo and which one receives the lidocaine patch. After four hours of
application the right forearm patch will be removed the neurosensory testing will be repeated
on the right forearm. After completing the testing, capsaicin (10Ál, 10 mg/ml) will be
injected intradermally on the volar aspect of the right forearm. Elicited and spontaneous
pain scores, blood pressure, heart rate, and respiratory rate will be measured at the time of
injection and every 2. 5 minutes for 10 minutes. A McGill Pain Questionnaire will be
administered at the time of capsaicin injection only. Ten minutes after the capsaicin
injection, the hyperalgesic area will be established to von Frey hair, stroking, and heat;
the flare response will be outlined; and neurosensory testing will performed halfway between
the edge of this defined area and the capsaicin injection site. At the completion of the
testing on the right forearm, the left forearm patch will be removed and the procedures
described for the right forearm will be repeated for the left forearm.
Minimum age: 18 Years.
Maximum age: N/A.
- Age 18 and above
- Allergy to lidocaine
- Current painful condition
- Current use of analgesics for the treatment of pain
- Lack of ability to understand the experimental protocol and to adequately communicate
in English. The neurosensory testing we plan to perform requires the complete
cooperation and understanding of the subject. It would be impossible to perform these
studies on patients who do not adequately communicate in English.
Locations and Contacts
UCSD Center for Pain and Palliative Care, La Jolla, California 92037, United States
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Starting date: December 2005
Ending date: February 2006
Last updated: September 7, 2006