Study: Vaporized, Low-Potency Cannabis Mitigates Neuropathic Pain

Originally published at blog.NORML.org

The administration of vaporized, low THC cannabis is associated with reduced analgesia in subjects with neuropathic pain, according to clinical trial data published online by The Journal of Pain.

Investigators at the University of California, Davis Medical Center conducted a double-blind, placebo-controlled, crossover study evaluating the analgesic efficacy of vaporized cannabis in 39 subjects, the majority of whom were experiencing neuropathic pain despite traditional treatment. Subjects inhaled cannabis of either moderate THC (3.53 percent), low dose THC (1.29 percent), or zero THC (placebo). Subjects continued to take all other concurrent medications as per their normal routine during the 3- to 4-week study period. Spontaneous pain relief, the primary outcome variable, was assessed by asking participants to indicate the intensity of their current pain on a 100-mm visual analog scale (VAS) between 0 (no pain) and 100 (worst possible pain).

Researchers reported: “Both the low and medium doses proved to be salutary analgesics for the heterogeneous collection of neuropathic pain conditions studied. Both active study medications provided statistically significant 30% reductions in pain intensity when compared to placebo.”

They concluded: “Both the 1.29% and 3.53% vaporized THC study medications produced equal antinociception at every time point. … [T]he use of low doses could potentially be prescribed by physicians interested in helping patients use cannabis effectively while minimizing cognitive and psychological side effects. Viewed with this in mind, the present study adds to a growing body of literature supporting the use of cannabis for the treatment of neuropathic pain. It provides additional evidence of the efficacy of vaporized cannabis as well as establishes low-dose cannabis (1.29%) as having a favorable risk-benefit ratio.”

Previous clinical trials have indicated that inhaled cannabis can safety and effectively relieve various types of pain, particularly neuropathy — a hard-to-treat nerve condition often associated with cancer, HIV, spinal cord injury, diabetes, multiple sclerosis, and other conditions. These include the following double-blind, placebo-controlled (FDA gold-standard) studies:

Ware et al. 2010. Smoked cannabis for chronic neuropathic pain: a randomized controlled trial. CMAJ 182: 694-701.

Wilsey et al. 2008. A randomized, placebo-controlled, crossover trial of cannabis cigarettes in neuropathic pain. Journal of Pain 9: 506-521.

Ellis et al. 2008. Smoked medicinal cannabis for neuropathic pain in HIV: a randomized, crossover clinical trial. Neuropsychopharmacology 34: 672-80.

Abrams et al. 2007. Cannabis in painful HIV-associated sensory neuropathy: a randomized placebo-controlled trial. Neurology 68: 515-521.

Wallace et al. 2007. Dose-dependent Effects of Smoked Cannabis on Capsaicin-induced Pain and Hyperalgesia in Healthy Volunteers Anesthesiology 107: 785-796.

Separate clinical trial data also reports that inhaled “cannabis augments the analgesic effect of opioids” and therefore “may allow for opioid treatment at lower doses with fewer side effects.”

Since 1999, US sales of opiate drugs have tripled in number and in 2010, a record-setting 254 million prescriptions for opioids were filled in the United States — enough to medicate every American adult around the clock for a month. (In particular, the manufacturing of the drug Oxycodone has increased from 8.3 tons in 1997 to 105 tons in 2011, an increase of 1,200 percent.) Overdose deaths from the use of prescription painkillers are also now at record levels, totaling some 15,000 annually — more than triple the total a decade ago.

Full text of the study, “Low-dose vaporized cannabis significantly improves neuropathic pain,” appears in The Journal of Pain.