The Use of Medical Cannabis for Treatment of Chronic Neuropathic Pain: An Integrative Research Review

Chronic neuropathic pain is a common problem that affects patients globally. In the United States (US), Australia and Canada, chronic neuropathic pain treatment includes a substantial use of opioids, however, with the growing epidemic, alternative options are being sought. The use of medical cannabis as treatment for chronic pain is increasing in popularity as an alternative for opioids. The aim of this integrative research review (IRR) was to explore the efficacy of medical cannabis for chronic neuropathic pain treatment. PubMed and Google Scholar were used for literature search engines. Keywords used to retrieve articles were efficacy, medical cannabis, medical marijuana, non-cancer chronic pain, neuropathic pain, opioids, cannabinoid, and treatment. Inclusion criteria were articles published in the US, Canada, and Australia, and those written in the English language. Exclusion criteria were articles prior to 2010 and subjects less than 18 years of age. Eleven articles were included in the IRR: five systematic reviews of randomized controlled trials, one randomized controlled trial, two cross-sectional observational studies, one secondary data analysis, one prospective cohort study, and one historical cohort study. Pain was measured using the Visual Analog Scale (VAS), Descriptor Differential Scale (DDS), numerical rating scale, Brief Pain Inventory (BPI), and/or quality of life in these studies. Most results showed that medical cannabis was an effective treatment for the reduction of chronic neuropathic pain and increased quality of life, with the exception of the Australian prospective cohort study. Adverse effects of cannabis included short-term neurocognitive decline and worsening of psychiatric illness. Cannabis was also associated with a reduction or cessation of opioid use in the US and Canadian articles, prescribing patterns and spending in Medicare enrollees in states where medical cannabis laws were implemented. Findings suggest that clinical practice should include substituting medical cannabis for opioids in the long-term management of chronic neuropathic pain in countries with medical cannabis laws.