Medical Cannabis for the Treatment of Fibromyalgia

George Habib, MD, MPH; Suheil Artul, MD

Disclosures

J Clin Rheumatol. 2018;24(5):255-258. 

In This Article

Abstract and Introduction

Abstract

Background: Fibromyalgia is a chronic pain syndrome, characterized by chronic musculoskeletal pain, fatigue, and mood disturbances. There are nearly no data on the effect of medical cannabis (MC) treatment on patients with fibromyalgia.

Methods: Data were obtained from the registries of 2 hospitals in Israel (Laniado Hospital and Nazareth Hospital) on patients with a diagnosis of fibromyalgia who were treated with MC. After obtaining patient consent, demographic, clinical, and laboratory parameters were documented. All the patients also completed the Revised Fibromyalgia Impact Questionnaire regarding the period before and after MC treatment.

Results: Thirty patients were identified, and 26 patients were included in the study. There were 19 female patients (73%), and the mean age of the study group was 37.8 ± 7.6 years. The mean dosage of MC was 26 ± 8.3 g per month, and the mean duration of MC use was 10.4 ± 11.3 months. After commencing MC treatment, all the patients reported a significant improvement in every parameter on the questionnaire, and 13 patients (50%) stopped taking any other medications for fibromyalgia. Eight patients (30%) experienced very mild adverse effects.

Conclusions: Medical cannabis treatment had a significant favorable effect on patients with fibromyalgia, with few adverse effects.

Introduction

Fibromyalgia is one of the most common chronic pain syndromes.[1] It is characterized by diffuse musculoskeletal pain, in addition to extreme fatigue and mood and sleep disturbances.[1] The pathogenesis of fibromyalgia is not clear. It usually affects women more than men and has a genetic preponderance.[2] Its prevalence in the general population is estimated to be approximately 7%, and it is more common among women than men.[3]

Fibromyalgia can have tremendous physical, as well as psychological, impacts on patients.[4] For example, many patients may be unable to accomplish various tasks at work and home, resulting in physical disability, which can be accompanied by anxiety and depression. Unfortunately, in most patients, fibromyalgia is chronic, and the main treatment is pain control medications. These medications include simple analgesics, pregabalin, and opiates.[5,6] Patients with fibromyalgia may also benefit from tricyclic antidepressants, benzodiazepines, and other types of antidepressants.[7] However, many of these medications are associated with adverse effects, which affect compliance. As a result, many patients with fibromyalgia experience continuous pain.

Cannabis is derived from the cannabis plant and is considered an illicit drug in most countries, including Israel. However, it is widely used illegally or legally in some countries where cannabis use is not outlawed.[8] The 2 main cannabis plant species are Cannabis sativa and Cannabis indica.[9] Most species today are a hybrid of the two, with cannabis derived from C. sativa designed mainly for morning or daytime use because it induces "energy" and cannabis derived from C. indica reserved primarily for evening or nighttime use because it induces calmness and good sleep.[10] The flowers of the cannabis plant contain more than 100 types of phytocannabinoids. Most research has focused on Δ-9-tetrahydrocannabinol and cannabidiol, both of which have the highest concentrations of phytocannabinoids.[11] There are 2 known receptors of endogenous cannabinoids (endocannabinoids): CB1 and CB2.[12] CB1 is mainly found in the central nervous system.[12] CB2 is found in different organs of the body, with its activities mainly related to the immune system.[12] Δ-9-Tetrahydrocannabinol is a partial agonist for the CB1 and CB2 receptors, and cannabidiol is an antagonist. Activation of CB1 results in a decrease in synaptic signals and neurological excitability.[13]

In recent years, cannabis had been legislated in some states in the United States for medical use, as well as in some countries in Europe.[14,15] In Israel, medical cannabis (MC) is licensed by the Israeli Medical Cannabis Agency of the Ministry of Health for patients with specific indications, including cancer with uncontrolled pain, Crohn disease with uncontrolled gastrointestinal symptoms, uncontrolled seizures, uncontrolled Parkinson disease, posttraumatic stress disorder, and unresponsive diabetic neuropathy. Requests for an MC license are submitted by the specialist taking care of the patient. Based on the recommendations of the Israeli Rheumatology Association, fibromyalgia is not included in the list of indications for MC. However, approval for MC treatment may be granted in some cases of fibromyalgia, especially for fibromyalgia patients who are also receiving treatment by other subspecialties, such as pain clinics, orthopedics (for discopathy), psychiatrists, and/or gastroenterologists (for irritable bowel syndrome). In most cases, following approval, the starting dose of MC is 20 g per month. The drug may be supplied directly to the patient every month or collected from a distribution center. Initially, the patient will be instructed in the use of MC by the supply team, and the patient may choose the mode of consumption (i.e., smoking, vaporization, oral oil drops, or a combination of these). There are 8 suppliers of MC in Israel, and the patient has the right to choose the company that supplies the MC. The patient is advised to consume the same amount of MC daily to prevent a shortage of MC by the end of the month.

There are only a few studies in the literature on the use of cannabis by fibromyalgia patients.[16,17] In these studies, the patients used unlicensed cannabis from different suppliers, and the studies contained no information on either the type or amount (in grams) of cannabis used. In general, the patients in these studies reported favorable effects of cannabis use. A systematic review of the use of synthetic cannabinoids in fibromyalgia (nabilone, 2 studies) found evidence (very low quality) of a greater reduction in pain and limitations in health-related quality of life in the synthetic cannabinoid group as compared with a placebo group in 1 study and better effects of synthetic cannabinoids on sleep than amitriptyline in another study.[18] The aim of the present study was to examine the effects of licensed MC on patients with fibromyalgia in an Israeli population.

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