Cannabidiol (CBD) for Fibromylagia Pain
Medicinal cannabis has been studied for cancer pain, chronic non-cancer pain, fibromyalgia, migraine, neuropathic pain, visceral pain, and other types of pain. The U.S. cannabis oil market has also exploded to a cool $950 million. But how effective is it? Let’s separate the fact from the fiction.
What are Cannabinoids?
The body contains naturally occurring cannabinoids and receptors for cannabinoids, called endocannabinoids. Cannabinoid receptors are naturally found in the peripheral and central nervous system (CNS) where cannabinoids act as neurotransmitters. They are also found in bone, the gut, and the immune system. These receptors are utilized for energy balance, neuroendocrine balance, immune and inflammatory responses, and many other functions. Endocannabinoids can cross the blood-brain barrier to effect the pain experience. A classic example of endocannabinoid function is the “runner’s high” experienced during endurance exercise.
Receptors for endocannibinoids are more numerous than opioid receptors. For this reason, these receptors have long been studied as potential drug targets for various types of pain.
Cannabinoids found in nature include components of the marijuana plant. This medicinal plant has been used for millennial for pain, but also is known to have effects on appetite, mood, and sleep. Given its high medicinal potential and less political demonization, more focus is now placed on clinical trials and educated usage.
Difference between THC and CBD
The cannabis plant itself contains over 450 phyto-cannibinoids. The primary components studied for their medicinal use are THC, the psychoactive component, and cannabidiol (CBD), which is non-psychoactive.
Synthetic cannaboids are prescribe-able and may contain THC alone or in conjunction with CBD. It is believed that the combination product is best for pain reduction as these two components work synergistically to reduce pain and reduce adverse effects. Generally speaking, the percentage of THC and CBD of a product should always be carefully considered. Most studies have used small, titrated doses. Higher doses of THC are not surprisingly associated with increased side effects.
Cannibidiol can be derived from the hemp plant—a similar plant as marijuana. Hemp is legal to grow in all 50 U.S. states. To compare, hemp contains less than 0.3% THC, whereas marijuana can contain 15-40% THC.
Traditional Pain Relief for Fibromyalgia Not Good Enough
Current medications for fibromyalgia offer only modest benefits for chronic pain and have a high incidence of side effects. These include anticonvulsants such as gabapentin, and others in this class. Opioids are also commonly prescribed. The side effect profile and risks associated with medical cannabis are lower than for these other drugs. The National Pain Foundation's large-scale 2014 survey of 1,339 fibromyalgia patients revealed that more than 60% of patients reported no improvements at all with these FDA-approved medications. The same report showed better pain relief with the use of medical marijuana than these prescription drugs.
Cannabis for Pain Relief of Fibromyalgia
Allodynia, a common experience of those with ME/CFS and fibromyalgia, is reduced in those taking a THC/CBD product, Sativex. Allodynia is believed to be due to an over-sensitization of the central nervous system. This 5-week, randomized, double-blind, placebo-controlled study enrolled 125 patients who continued their customary prescribed pain relievers, such as opioids and anti-depressants. At the end of the study, participants who received the Sativex reported a 30% reduction in allodynia and improved sleep throughout the entire study.
A 2008 study examining the synthetic cannabinoid, Nabilone, showed modest pain relief for fibromyalgia. The study was double-blinded, randomized, and controlled using 40 individuals with a fibromyalgia diagnosis. Statistically significant reductions in pain were reported after 4 weeks of use, but pain relief diminished upon discontinuation. In another double-blind study, Nabilone was compared to amitriptyline in 29 fibromyalgia patients. At the end of the trial, Nabilone was more effective for sleep than amitriptyline.
Cannabidiol, CBD, has also been shown to reduce neuroinflammation by acting on microglia in the CNS in animals and some human studies. More study into these mechanisms will likely pave the way for future clinical trials of CBD in neuroinflammatory illnesses like ME/CFS and fibromyalgia.
Why the mixed results? There is a large degree of variability in cannabinoid studies for fibromyalgia and other painful conditions. For fibromyalgia specifically, the diagnostic process lacks the degree of precision of better defined conditions which may weaken study design. Dosing protocols have yet to be determined to assess effect and risk. Studies also use various formulations of synthetic cannabinoids which may give mixed results.
How to Use CBD
Various cannabidiol preparations are legally available in some parts of the world (e.g. US, Canada, Europe, Africa) and herbal cannabis has been recently legalized for therapeutic use in over 20 states in the US, Canada, and Israel.
Find specific legal information about your state here.
Smoking pure cannabis is the least preferred method of consumption due to inhalation of toxic products of smoke. The plant may however be vaporized and inhaled to reduce combustion toxins.
Other forms are available without prescription and without THC. These include vaporizing synthetic CBD oils, ingestion, and topical preparation. Most of these preparations are derived from hemp. Hemp oil contains CBD, but little to no THC. Topical cannabidiol products are also available for potential musculoskeletal pain relief. Research shows that there are cannabinoid receptors on the skin, but some absorption of the compounds occurs as well. No clinical trials have been performed examining topical CBD for pain.
Potential Concerns
Long term studies of cannabis in those with chronic pain have not been evaluated. As with any intervention, there are risks involved. Medicinal cannabis may cause short term psychomotor effects, dizziness, appetite change, memory deficits, and changes in mood (positive or negative). It may also increase blood pressure and heart rate. In some individuals, cannabis use may result in psychosis, though this is rare. There is no known risk of addiction with medicinal cannabis use.
Drug interactions may occur with medical cannabis use. Those also taking opioids have as much as a 20% increased risk of serious effect. The effects of cannabis may be augmented with concomitant use of alcohol, benzodiazepines, and anti-depressants. Medical cannabis is absolutely contraindicated in pregnant women, those under the age of 25, and those with a history of psychotic illness.
Risks and side effects are most common with high dose THC marijuana and synthetic CBD/THC formulations. These effects are less likely, or non-existent, with hemp-derived CBD oils. As always, ask your doctor.
Bottom Line
The Journal of Rheumatology issued a position statement on the use of medicinal cannabis for chronic pain. They state there is a lack of evidence to routinely recommend this treatment option. However, they encourage doctors to be knowledgeable of the possibility when other pain treatments fail. Doctors should be open to the idea of a trial of cannabinoids. Unfortunately bias and stigmatization still exist around the cannabis plant, but this should not completely discount the possibility of a trial when other medications are ineffective. Overall, the risk profile is far less than opioids, and other medications.
References
FDAReg Watch. "Marijuana Rated Significantly More Effective in Treating Fibromyalgia Symptoms than FDA-Approved Drugs, Global Survey Finds." Press release, April 21, 2014.
Walitt B. et al. (2016) Cannabinoids for fibromyalgia. Cochrane Database Syst Rev.; 7:CD011694.
Nurmikko TJ et al. (2007) Sativex successfully treats neuropathic pain characterised by allodynia: a randomised, double-blind, placebo-controlled clinical trial. Pain. 133(1-3):210-20
van de Donk T et al. (2018) An experimental randomized study on the analgesic effects of pharmaceutical-grade cannabis in chronic pain patients with fibromyalgia. Pain. doi: 10.1097/j.pain.0000000000001464
Fitzcharles MA et al (2019) Position Statement: A Pragmatic Approach for Medical Cannabis and Patients with Rheumatic Diseases. J Rheumatol. pii: jrheum.181120.
Pergolizzi JV, et al. (2018) The role of cannabinoids in pain control: the good, the bad, and the ugly. Minerva Anestesiologica. 84(8):955-69.
