A randomized, placebo-controlled, crossover trial of cannabis cigarettes in neuropathic pain.
The Food and Drug Administration (FDA), Substance Abuse and Mental Health Services Administration (SAMHSA), and the National Institute for Drug Abuse (NIDA) report that no sound scientific studies support the medicinal use of cannabis. Despite this lack of scientific validation, many patients routinely use "medical marijuana," and in many cases this use is for pain related to nerve injury. We conducted a double-blinded, placebo-controlled, crossover study evaluating the analgesic efficacy of smoking cannabis for neuropathic pain. Thirty-eight patients with central and peripheral neuropathic pain underwent a standardized procedure for smoking either high-dose (7%), low-dose (3.5%), or placebo cannabis. In addition to the primary outcome of pain intensity, secondary outcome measures included evoked pain using heat-pain threshold, sensitivity to light touch, psychoactive side effects, and neuropsychological performance. A mixed linear model demonstrated an analgesic response to smoking cannabis. No effect on evoked pain was seen. Psychoactive effects were minimal and well-tolerated, with some acute cognitive effects, particularly with memory, at higher doses.


CONCLUSIONS
This study adds to a growing body of evidence that cannabis may be effective at ameliorating neuropathic pain, and may be an alternative for patients who do not respond to, or cannot tolerate, other drugs. However, the use of marijuana as medicine may be limited by its method of administration (smoking) and modest acute cognitive effects, particularly at higher doses.
Wilsey
Barth
B
VA Northern California Health Care System, Department of Anesthesiology and Pain Medicine, University of California, Davis Medical Center, Davis, California, USA. blwilsey@ucdavis.edu
Marcotte
Thomas
T
Tsodikov
Alexander
A
Millman
Jeanna
J
Bentley
Heather
H
Gouaux
Ben
B
Fishman
Scott
S
D000328:Adult; D000339:Affect / Q000187:drug effects; D000368:Aged; D002186:Cannabinoids / Q000008:administration & dosage*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D006801:Humans; D016014:Linear Models; D008385:Marijuana Smoking; D008875:Middle Aged; D009437:Neuralgia / Q000188:drug therapy* / Q000523:psychology*; D009483:Neuropsychological Tests; D010147:Pain Measurement; D013997:Time Factors
D002186:Cannabinoids