There is currently little conclusive evidence to suggest a benefit of cannabis use for the management of neuropathic pain, according to findings from a literature review published in the Annals of Internal Medicine.1
Researchers reviewed 13 systematic reviews and 62 primary studies to evaluate the effects of cannabis use on chronic pain, including neuropathic pain, multiple sclerosis-associated pain, and cancer pain. There was low-strength evidence suggesting a beneficial effect of cannabis on relieving neuropathic pain, but these findings were not clinically significant.
In 9 studies, patients undergoing intervention did experience higher relief from pain of at least 30% from baseline (risk ratio, 1.43; 95% CI, 1.16-1.88; I2 = 38.6%; P =.111). The standard Cochran chi-square test with I2 was used to assess “the magnitude of statistical heterogeneity among the studies.” Some studies demonstrated associations between cannabis use and pain relief in patients; however, these results were not significant.
High short-term adverse effects associated with cannabis use were noted in 2 systematic reviews, but these also did not reach statistical significance. Dizziness, lightheadedness, agitation, and even suicide attempts were adverse events reported in some studies using cannabis to manage chronic pain.
The investigators concluded that, to optimize patient outcomes and reduce treatment-related harms, clinicians “will still need to engage in evidence-based discussions with patients managing chronic pain who are using or requesting to use cannabis.”
Study Limitations
The researchers comment that many of the studies in this review used patient populations that were highly selected. In addition, many studies rarely included patients who were chronically ill or had a lengthy history of cannabis use, factors that would provide greater insight into the long-term adverse effects or harms associated with cannabis.
Reference
- Nugent SM, Morasco BJ, O’Neil ME, et al. The effects of cannabis among adults with chronic pain and an overview of general harms: a systematic review. Ann Intern Med. 2017;167(5):319-331.