Low-Dose Vaporized Cannabis Significantly Improves Neuropathic Pain

• Published in: The journal of pain Vol. 14; no. 2; pp. 136 - 148
• Main Authors: Wilsey, Barth, Marcotte, Thomas, Deutsch, Reena, Gouaux, Ben, Sakai, Staci, Donaghe, Haylee
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.2013
• Subjects: Administration, Inhalation; Adult; Affect - drug effects; analgesia; Anesthesia & Perioperative Care; cannabis; Cannabis - adverse effects; Cannabis - chemistry; clinical trial; Cross-Over Studies; Dose-Response Relationship, Drug; Double-Blind Method; Dronabinol - analysis; Female; Humans; Hyperalgesia - etiology; Hyperalgesia - psychology; Linear Models; Male; Middle Aged; Neuralgia - drug therapy; Neuralgia - etiology; Neuralgia - psychology; Neuropathic pain; neuropsychological testing; Neuropsychological Tests; Pain Measurement; Pain Medicine; Pain Threshold - drug effects; Patient Selection; Phytotherapy - methods; Socioeconomic Factors; Treatment Outcome; Volatilization; clinical trial; cannabis; neuropsychological testing; analgesia; Neuropathic pain
• ISSN: 1526-5900; 1528-8447; 1528-8447
• DOI: 10.1016/j.jpain.2012.10.009

Abstract We conducted a double-blind, placebo-controlled, crossover study evaluating the analgesic efficacy of vaporized cannabis in subjects, the majority of whom were experiencing neuropathic pain despite traditional treatment. Thirty-nine patients with central and peripheral neuropathic pain underwent a standardized procedure for inhaling medium-dose (3.53%), low-dose (1.29%), or placebo cannabis with the primary outcome being visual analog scale pain intensity. Psychoactive side effects and neuropsychological performance were also evaluated. Mixed-effects regression models demonstrated an analgesic response to vaporized cannabis. There was no significant difference between the 2 active dose groups' results ( P > .7). The number needed to treat (NNT) to achieve 30% pain reduction was 3.2 for placebo versus low-dose, 2.9 for placebo versus medium-dose, and 25 for medium- versus low-dose. As these NNTs are comparable to those of traditional neuropathic pain medications, cannabis has analgesic efficacy with the low dose being as effective a pain reliever as the medium dose. Psychoactive effects were minimal and well tolerated, and neuropsychological effects were of limited duration and readily reversible within 1 to 2 hours. Vaporized cannabis, even at low doses, may present an effective option for patients with treatment-resistant neuropathic pain. Perspective The analgesia obtained from a low dose of delta-9-tetrahydrocannabinol (1.29%) in patients, most of whom were experiencing neuropathic pain despite conventional treatments, is a clinically significant outcome. In general, the effect sizes on cognitive testing were consistent with this minimal dose. As a result, one might not anticipate a significant impact on daily functioning.