According to a systemic review of randomized controlled trials published in the British Journal of Clinical Pharmacology, cannabis inhalation and the administration of cannabinoids are both associated with “significant analgesic effects” in the treatment of chronic non-cancer pain.
A literature review regarding the efficacy of cannabinoids in the treatment of chronic pain, including neuropathic pain, fibromyalgia, rheumatoid arthritis, and mixed chronic pain was conducted by investigators from the University of Toronto, Hospital for Sick Children. Eighteen randomized controlled trials that were published between 2003 and 2010 involving a total of 766 participants met inclusion criteria. For of the trials evaluated inhaled cannabis, while other studies assessed the analgesic properties of either plant-derived cannabinoids or synthetic cannabinoids.
“Overall the quality of trials was excellent,” authors wrote. “Fifteen of the eighteen trials that met inclusion criteria demonstrated a significant analgesic effect of cannabinoid as compared to placebo, several reported significant improvements in sleep. There were no serious adverse effects.”
It was noted by the researchers that all four trials involving inhaled cannabis “found a positive effect with no serious adverse side effects.” They added: “Of special importance is the fact that two of the trials examining smoked cannabis demonstrated a significant analgesic effect in HIV neuropathy, a type of pain that has been notoriously resistant to other treatments normally used for neuropathic pain. In the trial examining cannabis based medicines in rheumatoid arthritis a significant reduction in disease activity was also noted, this is consistent with pre-clinical work demonstrating that cannabinoids are anti-inflammatory.”
Investigators concluded, “[C]annabinoids are a modestly effective and safe treatment option for chronic non-cancer (predominantly neuropathic) pain. Given the prevalence of chronic pain, its impact on function and the paucity of effective therapeutic interventions, additional treatment options are urgently needed. More large-scale trials of longer duration reporting on pain and level of function are required.”
Cannabinoids for treatment of chronic non-cancer pain; a systemic review of randomized trials-British Journal of Pharmacology