Studies have shown that marijuana is especially effective in treating neuropathic pain, commonly seen in multiple sclerosis, HIV/AIDS, and other ailments, and notoriously resistant to treatment with conventional pain drugs, including opiates. Preclinical research as well as case series and anecdotal reports suggest that marijuana use may allow reduced opioid doses when given in combination
(1) Donald Abrams, et al., “Cannabis in Painful HIV-Associated Sensory Neuropathy: a Randomized Placebo-Controlled Trial,” Neurology 68, no. 7 (2007): 515-21.
This clinical trial involved HIV/AIDS patients suffering from HIV-associated sensory neuropathy, a painful condition estimated to eventually afflict up to one third of HIV-infected persons. There are presently no FDA-approved treatments for this indication. Donald Abrams and his colleagues tested the efficacy of smoked marijuana on both HIV neuropathy and a type of laboratory-induced pain. Smoked marijuana produced an average 34% reduction in pain and was well tolerated.
(2) R.J. Ellis, et al., “Smoked Medicinal Cannabis For Neuropathic Pain in HIV: a Randomized, Crossover Clinical Trial,” Neuropsychopharmacology 34, no. 3 (2009): 672-80.
This trial focused on patients with HIV-associated neuropathy refractory to at least two previous analgesic classes. Ellis and colleagues reported, “In the present experiment, cannabis reduced pain intensity and unpleasantness equally. Thus, as with opioids, cannabis does not rely on a relaxing or tranquilizing effect, (e.g. anxiolysis) but rather reduces both the core component of nociception and the emotional aspect of the pain experience to an equal degree. ... In general, side effects and changes in mood were inconsequential.”
(3) B. Wilsey, et al., “A Randomized, Placebo-Controlled, Crossover Trial of Cannabis Cigarettes in Neuropathic Pain,” Journal of Pain 9, no. 6 (2008):506-21.
This study investigated the efficacy of smoked marijuana in patients suffering from neuropathic pain related to a variety of conditions, including multiple sclerosis, spinal cord injury, diabetes, and complex regional pain syndrome. Wilsey and colleagues concluded, “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.”
(4) David Baker, et al., “The Therapeutic Potential of Cannabis,” The Lancet Neurology 2, no. 5 (2003): 291-8.
This review, written prior to publication of the clinical trials described above, discussed in detail the biochemical basis for marijuana’s analgesic effects. It also discussed the drawbacks of oral dosing, explaining that “oral administration is probably the least satisfactory route for cannabis owing to sequestration of cannabinoids into fat from which there is slow and variable release into plasma. In addition, significant first-pass metabolism in the liver, which degrades THC, contributes to the variability of circulating concentrations of orally administered cannabinoids, which makes dose titration more difficult and therefore increases the potential for adverse psychoactive effects. Smoking has been the route of choice for many cannabis users because it delivers a more rapid ‘hit’ and allows more accurate dose-titration.”
(5) M.E. Lynch, J. Young, A.J. Clark, “A Case Series of Patients Using Medicinal Marijuana for Management of Chronic Pain Under the Canadian Marijuana Medical Access Regulations,” Journal of Pain and Symptom Management 32, no. 5 (2006): 497-501.
This case series is based on 30 patients qualified to use medical marijuana under Canadian regulations, seen at a pain management center in Nova Scotia. All suffered from chronic, severe pain that had not responded to conventional approaches. On an 11-point scale, 93% reported pain relief equal to 6 or greater, and many reported relief of other symptoms such as spasticity, poor sleep, nausea, and vomiting. 70% reported being “able to decrease use of other medications that had been causing side effects (e.g., NSAIDs, opioids, and antidepressants).”
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