Effects of Smoked Marijuana on Neuropathic Pain
To determine if smoking marijuana will reduce neuropathic pain without causing too much drowsiness or feeling "too dopey".
|Study Design:||Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
|Official Title:||A Double Blind, Active Placebo Controlled Crossover Trial of the Antinociceptive Effect of Smoked Marijuana on Subjects With Neuropathic Pain; Correlation With Changes in Mood, Cognition, and Psychomotor Performance|
- Score on a series of pain scales (heat pain threshold, VAS intensity, VAS unpleasantness, pain relief, neuropathic pain scale).
- Number of subjects who are unable to tolerate the high dose without significant side effects.
- Changes in mood, cognitive impairment, and psychomotor performance (mood - VAS happiness, cognition - Digit Symbol Modalities Test, psychomotor performance - Grooved Pegboard Test).
|Study Start Date:||November 2003|
|Study Completion Date:||February 2006|
|Primary Completion Date:||February 2006 (Final data collection date for primary outcome measure)|
High dose cannabis (7.5% THC by weight)
Low dose cannabis (3.5% THC by weight)
Placebo Comparator: 3
The case for marijuana's medical use for pain is primarily from experimental studies with normal subjects, which have yielded conflicting results. Experimental subjects have been shown to have significant dose-dependant antinociception effect that is not reversed by opioid antagonism. In contrast to this positive antinociceptive effect, other experiments demonstrated hyperalgesic activity and probably enhancement of the perception of pain upon acute exposure in chronic users of marijuana.
In addition to studying spontaneous pain antinociception, it would be useful to evaluate the response to marijuana following evoked pain. Such evoked pain is produced by stimulation of the skin that is normally not noxious.
Because of the potential side effects of marijuana administration, one of the aims of the present study is to analyze inter-individual variability and the occurrence of dose-dependant analgesia of marijuana with an eye on defining tolerable dosing in clinical neuropathic pain syndromes.
Comparisons: Neuropathic and experimentally induced pain scores will be compared after the administration of escalating doses of low, high, and placebo marijuana cigarettes as provided by the National Institutes on Drug Abuse (NIDA).
|United States, California|
|UC Davis Medical Center|
|Sacramento, California, United States, 95817|
|Principal Investigator:||Barth L Wilsey, M.D.||University of California, Davis|