Low-Dose Vaporized Cannabis Significantly Improves Neuropathic Pain

Published:December 13, 2012DOI:


      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.


      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.

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      Linked Article

      • Marijuana for Pain Relief: Don't Jump to Conclusions
        The Journal of PainVol. 14Issue 10
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          The title of Wilsey et al's recent study “Low-Dose Vaporized Cannabis Significantly Improves Neuropathic Pain”24 piqued our interest, as did the abstract that compared the calculated numbers-needed-to-treat of 2.9 to 3.2 favorably to “traditional neuropathic pain medications.” The abstract describes minimal psychoactive effects and deems the overall results as “a clinically significant outcome.” Unfortunately, these conclusions are not borne out by careful examination of this study and contrasting it with other available treatments.
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