Fibromyalgia (FM) is a chronic pain syndrome of unknown etiology. The disease is characterized by widespread musculoskeletal pain, fatigue and multiple tender points in the neck, spine, shoulders and hips. An estimated 3 to 6 million Americans are afflicted by fibromyalgia, which is often poorly controlled by standard pain medications.
Fibromyalgia patients frequently self-report using cannabis therapeutically to treat symptoms of the disease,[1-4] and physicians – in instances where it is legal for them do so – often recommend the use of cannabis to treat musculoskeletal disorders.[5-6] To date, however, there are few clinical trials assessing the use of cannabinoids to treat the disease.
Writing in the journal Current Medical Research and Opinion, investigators at Germany's University of Heidelberg evaluated the analgesic effects of oral THC in nine patients with fibromyalgia over a 3-month period. Subjects in the trial were administered daily doses of 2.5 to 15 mg of THC and received no other pain medication during the trial. Among those participants who completed the trial, all reported a significant reduction in daily recorded pain and electronically induced pain.
Another study published in The Journal of Pain reported that the administration of the synthetic cannabinoid nabilone significantly decreased pain in 40 subjects with fibromyalgia in a randomized, double-blind, placebo-controlled trial. "As nabilone improved symptoms and was well-tolerated, it may be a useful adjunct for pain management in fibromyalgia," investigators concluded. A separate 2010 trial performed at McGill University in Montreal reported that low doses of nabilone significantly improved sleep quality in patients diagnosed with the disease. However, a recent literature review has criticized these papers as being relatively low quality.
A 2011 observational, case-control trial reported that the use of whole-plant cannabis is associated with beneficial effects on various symptoms of fibromyalgia, including the relief of pain and muscle stiffness. Investigators at the Institut de Recerca Hospital del Mar in Barcelona, Spain assessed the associated benefits of cannabis in patients with fibromyalgia compared with FM patients who did not use the substance. Twenty-eight users and non-users participated in the study.
Authors reported: "Patients used cannabis not only to alleviate pain but for almost all symptoms associated to FM, and no one reported worsening of symptoms following cannabis use. ... Significant relief of pain, stiffness, relaxation, somnolence, and perception of well-being, evaluated by VAS (visual analogue scales) before and two hours after cannabis self-administration was observed." Cannabis users in the study also reported higher overall mental health summary scores than did non-users. Investigators concluded: "The present results together with previous evidence seem to confirm the beneficial effects of cannabinoids on FM symptoms."
Literature reviews of various types of cannabis preparations report that cannabinoids are efficacious in alleviating various types of pain, including pain due to neuropathy, musculoskeletal disorders, fibromyalgia, and other chronic conditions. (Please see the 'Chronic Pain' section of this book for further details.) Further, cannabinoids' immune-modulating effect also make them promising agents for the treatment of fibromyalgia and other related conditions.[13-16]
 Swift et al. 2005. Survey of Australians using cannabis for medical purposes. Harm Reduction Journal 4: 2-18.
 Ware et al. 2005. The medicinal use of cannabis in the UK: results of a nationwide survey. International Journal of Clinical Practice 59: 291-295.
 Ste-Marie et al. 2012. Association of herbal cannabis use with negative psychosocial parameters in patients with fibromyalgia. Arthritis Care & Research 64: 1202-1208.
 Trout and DiDonato. 2015. Medical cannabis in Arizona: Patient characteristics, perceptions, and impressions of medical cannabis legalization. Journal of Psychoactive Drugs 47: 259-266.
 Dale Gieringer. 2001. Medical use of cannabis: experience in California. In: Grotenhermen and Russo (Eds). Cannabis and Cannabinoids: Pharmacology, Toxicology, and Therapeutic Potential. New York: Haworth Press: 153-170.
 Schley et al. 2006. Delta-9-THC based monotherapy in fibromyalgia patients on experimentally induced pain, axon reflex flare, and pain relief. Current Medical Research and Opinion 22: 1269-1276.
 Skrabek et al. 2008. Nabilone for the treatment of pain in fibromyalgia. The Journal of Pain 9: 164-173.
 Ware et al. 2010. The effects of nabilone on sleep in fibromyalgia: results of a randomized controlled trial. Anesthesia and Analgesia 110: 604-610.
 Fiz et al. 2011. Cannabis use in patients with fibromyalgia: Effect on symptoms relief and health-related quality of life. PLoS One 6 [open access journal].
 Beaulieu et al. 2016. Medical cannabis: considerations for the anesthesiologist and pain physician. Canadian Journal of Anaesthesia 63: 608-624.
 Katz et al. 2017. Medical cannabis: Another piece in the mosaic of autoimmunity? Clinical Pharmacology and Therapeutics 101: 230-238.
 Ethan Russo. 2004. Clinical endocannabinoid deficiency (CECD): Can this concept explain therapeutic benefits of cannabis in migraine, fibromyalgia, irritable bowel syndrome and other treatment-resistant conditions? Neuroendocrinology Letters 25: 31-39.
 Smith and Wagner. 2014. Clinical endocannabinoid deficiency (CECD) revisited: can this concept explain the therapeutic benefits of cannabis in migraine, fibromyalgia, irritable bowel syndrome and other treatment-resistant conditions? Neuroendocrinology Letters 35: 198-201.
 Ethan Russo. 2016. Clinical endocannbinoid deficiency reconsidered: Current research supports the theory in migraine, fibromyalgia, irritable bowel, and other treatment-resistent syndromes. Cannabis and Cannabinoid Research 1: 154-165.