Understanding the Relationship Between CBD and Pain

The statements mentioned in this content have not been evaluated by the FDA, and are not intended to prevent, diagnosis, or treat any disease. Always work with your personal healthcare provider.

by Chris D. Meletis, ND, and Kimberly Wilkes 

The endocannabinoid system within our bodies regulates many aspects of health including pain control. This system is comprised of endocannabinoids produced within the body including anandamide (arachi-donylethanolamide) and 2-arachidonylblycerol (2-AG), which are able to activate receptors in the endocannabinoid system. The presence of this system was an intriguing discovery as it indicated our bodies produce substances similar to cannabis that are able to switch endocannabinoid receptors on and off.

Two important receptors in this system that are involved in pain management are cannabinoid 1 (CB1),1  Activation of CB2 receptors suppresses the pain response to thermal and mechanical stimuli,1,2 thermal and tactile hypersensitivity produce by peripheral inflammation2-4 and neuropathic pain.6  As with endocannabinoids produced in the body, phytocannabinoids such as A-tetrahydrocannabinol (THC), the psychoactive component of Cannabis Sativa plant and cannabidiol (CBD), a non-psychoactive component, are able to activate endocannabinoid receptors.

Endocannabinoids can indirectly work through the same receptors as opioid drugs to control pain.   CB2 receptors found in primary afferent pathways.7 Furthermore, CB2 expression is weak in the areas of the brain stem that regulate respiration.  This suggests that respiratory depression, a potentially fatal adverse effect of opioid drugs would not occur when using phytocannabinoids as painkillers.1

An extensive amount of evidence points to the endocannabinoid system’s role in the management of pain causes by a wide spectrum of conditions.  The article will focus exclusively on endocannabinoid and phytocannabinoid regulation of two common types of pain:  muscle and visceral pain.

Musculoskeletal Pain, Fibromyalgia, and Temporomandibular Disorders

Chronic widespread musculoskeletal pain is a common disorder occurring in approximately 10% of the population.2 A subgroup of patients with this type of pain have fibromyalgia which occurs in 3% to 5% of the population.8  In women with musculoskeletal pain, levels of the endocannabinoids oleoylethanolamide and stearoylethanalamide were altered compared with healthy controls.9

Endocannabinoid alternations are thought to play a role in fibromyalgia and its frequent comorbidities such as migraines and irritable bowel syndrome.20 A hallmark of fibromyalgia is sore muscles. The pain usually occurs in similar locations in different patients suffering from this disorder.  Studies indicate there is an association between fibromyalgia and endocannabinoid deficiency and this deficiency may play a role in the sore muscles of this condition.19-22 For this reason, cannabinoids are thought to be useful in chronic pain conditions such as myofascial pain syndrome and temporomandibular joint pain (TMI).14

CBD has analgesic and anti-inflammatory effects that may prove beneficial in disorders that involve muscle pain.18 CBD was first isolated in 1940 but it is only relatively recently that its full potential was realized due to studies showing its antioxidative, anti-inflammatory and neuroprotective effects.14 Some of these actions are independent of the CB1 and CB2 receptors.15

In studies using rodent models of inflammation, CBD reduces migration and infiltration of inflammatory cells (neutrophils).10 Cannabinoids are also thought to reduce inflammation by increasing the generation of eicosanoids signaling molecules involved in regulating inflammation and pain.17 In addition, CBD lowers production of the inflammatory cytokine TNF-a and reduces fatty acid amidahyrolase (FAAH) activity, an enzyme that degrades the anti-inflammatory endocannabinoid anadamide.17 CBD’s reduction in FAAH causes a raise in anandamide production.17 In animal and cell culture studies, CBD has demonstrated an anti-inflammatory effect that is several hundred times greater than aspirin.14 CBD’s analgesic properties are due to mechanisms that include acting as a lipoxygenase inhibitor, increasing the release of prostaglandin (PGE2) from synovial cells and blocking of leukotriene B4 in human plymorphonuclear cells.13