Chronic Pain


An estimated one in five US adults suffers from a chronic pain condition of a duration of six months or more and requiring medical intervention. Nearly half of these patients report that their pain persists despite the use of conventional pain medicines, such as NSAIDS and opioids. Health economists estimate that the annual cost of chronic pain in the United States is $635 billion in health care costs and lost productivity.[1]

Cannabis and cannabinoids – as well as specific flavonoids (phytonutrients) in the plant[2] — are well-documented to possess pain-relieving properties. Recent reviews of the clinical literature identify dozens of controlled studies, involving thousands of patients, documenting the safety and efficacy of cannabinoids in pain management.[3] A 2017 review of over 10,000 peer-reviewed scientific papers by the National Academies of Sciences, Engineering, and Medicine acknowledged, “In adults with chronic pain, patients who [are] treated with cannabis or cannabinoids are more likely to experience a clinically significant reduction in pain symptoms. … There is conclusive or substantial evidence that cannabis is effective for the treatment of chronic pain in adults.”[4]

Numerous gold-standard (randomized, placebo-controlled) trials document the ability of either inhaled or vaporized herbal cannabis to significantly mitigate pain in various populations as well as in healthy volunteers exposed to laboratory-induced pain.[5-6] Specifically, several trials report clinically significant reductions in pain in patients with HIV,[7-8] diabetes,[9] spinal cord injury,[10] or with severe treatment-resistant neuropathy (nerve pain),[11-13] among other chronic conditions. These positive results have been replicated in clinical trials utilizing relatively low doses of cannabis[14-15] as well as in trials using plant-derived cannabis extracts.[16-17]

Longitudinal data further shows that cannabis provides patients with continued pain relief long term without producing significant adverse side effects,[18] including among elderly populations.[19-20]

The co-administration of either smoked cannabis or oral cannabinoids has been documented to augment the pain-relieving effects of opioids. In one study, vaporized herbal cannabis was demonstrated to enhance the pain-relieving activity of morphine and oxycodone in chronic pain subjects, therefore potentially allowing “for opioid treatment at lower doses with fewer side effects.”[21] Another study reported similarly enhanced analgesic efficacy when low doses of oral THC were combined with hydromorphone (aka Dilaudid). Authors reported, “These data … are indicative of [the] possible opioid-sparing effects” of cannabinoids.[22] These synergistic effects have also been documented in settings where subjects were provided with only sub-therapeutic doses of cannabis and opioids.[23]

Numerous studies of various patient populations, including those with chronic pain,[24-25] cancer,[26] fibromyalgia,[27] multiple sclerosis,[28] and other conditions, consistently find that subjects taper or even eliminate their use of prescription pain medications following the use of cannabis.[29-30] There are now dozens of peer-reviewed papers documenting this trend. Some observational studies have similarly reported reductions in opioid-related mortality following the enactment of marijuana access.[31-33]

Not surprisingly, among patients enrolled in state-specific medical cannabis access programs, over 65 percent are registered to use the substance for the treatment of chronic pain.[34] This is the most commonly reported qualifying condition among active US cardholders.

The use of cannabis for pain, and as a potential substitute for opioids and other prescription analgesics, is rapidly becoming more accepted among clinicians,[35-36] with a coalition of physicians in 2020 issuing “consensus-based recommendations surrounding the safe introduction and titration of cannabinoids in concert with tapering opioids.”[37]


[1] Science-Daily, September 11, 2012, “Chronic pain costs U.S. up to $635 billion, study shows.”

[2] Medical Xpress, July 24, 2019, “Researchers unlock access to pain relief potential of cannabis.”

[3] Grotenhermen and Muller-Vahl. 2017. Medicinal uses of marijuana and cannabinoids. Critical Reviews in Plant Sciences 35: 378-405.

[4] National Academies of Sciences, Engineering, and Medicine. 2017. The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research.

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

[6] Cooper et al. 2013. Comparison of the analgesic effects of dronabinol and smoked marijuana in daily marijuana smokers. Neuropsychopharmacology 38: 1984-1992.

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

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

[9] Wallace et al., 2015. Efficacy of inhaled cannabis on painful diabetic neuropathy. Journal of Pain 7: 616-627.

[10] Wilsey et al. 2016. An exploratory human laboratory experiment evaluating vaporized cannabis in the treatment of neuropathic pain from spinal cord injury and disease. The Journal of Pain 17: 982-1000.

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

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

[13] Eisenberg et al. 2014. The pharmacokinetics, efficacy, safety, and ease of use of a novel portable metered-dose cannabis inhaler in patients with chronic neuropathic pain: a phase 1a study. Journal of Pain and Palliative Care Pharmacotherapy 28: 216-225.

[14] Wilsey et al. 2013. Low-dose vaporized cannabis significantly improves neuropathic pain. The Journal of Pain 14: 136-148.

[15] Almog et al. 2020. The pharmacokinetics, efficacy, and safety of a novel selective-dose inhaler in patients with chronic pain: A randomized, double-blinded, placebo-controlled trial. European Journal of Pain 24: 1505-1516.

[16] Johnson et al. 2009. Multicenter, double-blind, randomized, placebo-controlled, parallel-group study of the efficacy, safety and tolerability of THC: CBD extract in patients with intractable cancer-related pain. Journal of Symptom Management 39: 167-179.

[17] Kawka et al., 2021. Clinical outcome data of first cohort of chronic pain patients treated with cannabis-based sublingual oils in the United Kingdom – analysis from the UK Medical Cannabis RegistryJournal of Clinical Pharmacology [online ahead of print]. 

[18] Ware et al. 2015. Cannabis for the Management of Pain: Assessment of Safety Study. Journal of Pain. 16: 1233-1242.

[19] Lum et al. 2019. Patterns of Marijuana Use and Health Impact: A Survey Among Older Coloradans. Gerontology & Geriatric Medicine 5 [open access publication].

[20] Abuhasira et al. 2018. Epidemiological characteristics, safety and efficacy of medical cannabis in the elderly. European Journal of Internal Medicine 49: 44-50.

[21] Abrams et al. 2011. Cannabiniod-opioid interaction in chronic pain. Clinical Pharmacology & Therapeutics 90: 844-851.

[22] Dunn et al. 2021. Within-subject, double-blinded, randomized, and placebo-controlled evaluation of the combined effects of the cannabinoid dronabinol and the opioid hydromorphone in a human laboratory model. Neuropsychopharmacology [online ahead of print].

[23] Cooper et al., 2018. Impact of co-administration of oxycodone and smoked cannabis on analgesia and abuse liability, Neuropsychopharmacology 43:2046-2055.

[24] Boehnke et al. 2016. Medical cannabis use is associated with decreased opiate medication use in a retrospective cross-sectional survey of patients with chronic pain. The Journal of Pain 17: 739-744

[25] Reiman et al., 2017. Cannabis as a substitute for opioid-based pain medication: Patient self-report. Cannabis and Cannabinoid Research 2: 160-166.

[26] Zylla et al. 2021. A randomized trial of medical cannabis patients with stage IV cancers to assess feasibility, dose requirements, impact on pain and opioid use, safety, and overall patient satisfaction. Supportive Care in Cancer [online ahead of print].

[27] Manuela Mazza. 2021. Medical cannabis for the treatment of fibromyalgia syndrome: A retrospective, open-label case series. Journal of Cannabis Research [open access publication].

[28] McCormack et al. 2019. Multiple Sclerosis and use of medical cannabis: A retrospective review evaluating symptom outcomes. Neurology (Supplement).

[29] Meng et al. 2021. Patient-reported outcomes in those consuming medical cannabis: A prospective longitudinal observational study in chronic pain patients. Canadian Journal of Anaesthesia 68: 633-644.

[30] Lucas et al. 2021. Cannabis significantly reduces the use of prescription opioids and improves quality of life in authorized patients: Results of a large prospective study. Pain Medicine 22: 727-739.

[31] Powell et al. 2015. Do medical marijuana laws reduce addictions and deaths related to pain killers? NBER Working Paper No. 21345.

[32] Averett and Smith. 2019. Medical marijuana laws and their effect on opioid related mortality. Economics Bulletin [open access journal].

[33] Hsu et al. 2021. Association between county level cannabis dispensary counts and opioid related mortality rates in the United States: panel data study. BMJ [open access journal].

[34] Boehnke et al., 2019. Qualifying conditions of medical cannabis license holders in the United States, Health Affairs 38: 295-302.

[35] Mark Collen. 2012. Prescribing cannabis for harm reduction. Harm Reduction Journal 9: 1.

[36] Sunil Aggerwal. 2012. Cannabinergic pain medicine: a concise clinical primer and survey of randomized-controlled trial results. The Clinical Journal of Pain 29: 162-171.

[37] Sihota et al. 2020. Consensus-based recommendations for titrating cannabinoids and tapering opioids for chronic pain control. International Journal of Clinical Practice [online ahead of print].