Working with Patients Using Cannabis: Education for Clinicians and Potential Alternative Treatments Available

The use of medical/recreational cannabis continues to grow and gain acceptance. Currently 36/50 states and the District of Columbia have legalized cannabis for at least medical purposes.1 Cannabis is a complex plant, with over 500 constituents including approximately 100 active compounds known as cannabinoids.2 Two seem most clinically relevant, Delta 9-tetrahydrocannabinol (THC) and Cannabidiol (CBD).2 While both have been studied for potential therapeutic effects, varying results are found in the research to date. According to the CDC, “Marijuana use may have a wide range of health effects on the body and brain.”3 However, while results have been more clinical and anecdotal, larger well controlled trials may not always substantiate those outcomes.2

Although there still remains a need for further high level studies, cannabis may be beneficial in treating those with chronic pain, inflammation, spasticity, GI issues, neurologic conditions (Parkinson’s, MS) as well as other conditions commonly seen in physical therapy.2  As use of cannabis becomes more common, physical therapists and other health care practitioners should be aware of the physiology and effects of cannabis, general education for patients interested in use, and alternative treatments like dry needling, or spinal manipulation which work similarly to marijuana in the opioid, and endocannabinoid systems.

THE ENDOCANNABINOID SYSTEM

            The endocannabinoid system (ECS) is a naturally occurring, vast network of chemical signals and receptors throughout our brain and body.4,5 Mainly consisting of two receptors, CB1 and CB2, the ECS helps regulate many critical bodily functions including but not limited to: central nervous system (CNS) development, pain/inflammation, the GI tract, mood, sleep, memory and movement.4,5 The two receptors can be stimulated by endogenous (naturally occurring endocannabinoids) or exogenous (plant derived cannabinoids) receptor agonists.4 Delta 9-THC (the psychoactive part of cannabis) binds mainly with CB1 but also CB2, while CBD (non-psychoactive) has a weaker affinity for both.6 CBD’s mechanisms are likely more multifold, acting on a variety of pathways in the opioid, cannabinoid, and other systems.6 CB1 (psychoactive) receptors are typically expressed in the CNS, GI, fatty tissue, liver, and skeletal muscle while CB2 receptors are more immune mediated in the tonsils, spleen, bone marrow, and enteric nervous system.4

THERAPEUTIC EFFECTS OF CANNABIS

A full-scale review of all the therapeutic effects of cannabis is beyond the scope of this article. While many studies exist, few are large scale and substantial in evidence. According to the National Academies of Sciences, Engineering, and Medicine, “Cannabis has conclusive or substantial evidence of effectiveness for adults with chronic pain, chemotherapy induced nausea/vomiting, Multiple Sclerosis, Epilepsy, and secondary sleep disturbances.7 Limited to moderate evidence exists for treatment of certain GI disorders, and in patients with Parkinson’s and Tourette’s syndromes.4 Many studies are limited to adult use, as use in adolescents has been shown to increase risk of developmental, cognitive, and emotional delays.3,4,7

Delta 9-THC’s chemical structure is an analogue of the neurotransmitter and endogenous opioid anandamide. Anandamide can mimic several of the pharmacological effects of THC without as many potential side effects or harm. THC provides antinociceptive effects by inhibiting presynaptic neurotransmitter release and modulation of post synaptic excitability in CB1 and CB2 receptors.4,6,8 However, this same pain-relieving process creates impaired thinking, and may interfere with a person’s ability to learn and perform complicated tasks.8 It also disrupts functioning of the cerebellum and basal ganglia, areas at least partially responsible for balance/posture and coordination.8,9

While CBD has less affinity for CB1 and CB2 receptors, it can antagonize them in the presence of THC.10,11 It is also thought to produce analgesic, anti-inflammatory, anti-convulsant and other effects via modulation of the immune response, without the psychoactive component.11 The pain reliving mechanisms seem to work through other ionic, and non-cannabinoid channels.11

Besides the well-known psychotropic effects, Cannabis has several different transient effects on the human body. Most research has focused on the respiratory and cardiovascular systems and to lesser extent the GI system.

EFFECTS ON THE CARDIOVASCULAR SYSTEM

The initial intake of THC increases heart rate (HR), may cause hypertension while sitting, and hypotension in standing.12,13,14 It raises resting heart rate, and chronic use can lead to bradycardia as well as increased sub-max HR, and sub-max oxygen demand during exercise.14,15 This increases risk for orthostatic hypotension, as demand is placed on the body to balance blood pressure and cardiac output. Clinicians therefore should be aware if their patients are using marijuana, as it may negatively affect the patient’s exercise performance.1,2,13,14,15 Marijuana also is associated with an increased risk of acute ischemic stroke, including an increased relative risk of stroke in users who were young (25–34 years of age)16

THE PULMONARY SYSTEM

In the lungs, cannabis causes bronchodilation at rest and potentially during exercise13. It is associated with an increase in phlegm production and coughing/wheezing with chronic use.13 Use of cannabis can lead to lung diffusion impairments, limiting the amount of oxygen successfully available during strenuous activity.13 Interestingly, several large published studies have reported that long-term cannabis only users have an increase in the forced vital capacity with little or no change in forced expiratory volume.17 ”A reduced FEV1/FVC ratio due to increased FVC clearly differs from the classical spirometric changes seen in tobacco smoking.”17 Method of ingestion can vastly effect how cannabis is synthesized in the pulmonary system, with edibles, and oromucosal options unlikely to produce the same airway restriction issues seen during smoking.

THE NEUROMUSCULAR SYSTEM

            The use of cannabis could positively affect exercise ability in people with underlying neurological conditions including Epilepsy, dystonias/movement disorders, Parkinson’s and Multiple Sclerosis.15,18 By aiding in relieving some of the sequala of these disorders including spasticity and poor coordination, more effective rehabilitative strategies may be developed. Another condition potentially benefitted with use of cannabis is Rheumatoid Arthritis. Activation of CB1 receptors by cannabinoids can lower sympathetic activity in the brain reducing neurotransmitter release, providing an anti-inflammatory effect.19 However, cannabis may have a sedative effect during exercise, resulting in reduced reaction time, coordination, and psychomotor performance.12,13,15

ALTERNATIVES TO CANNABIS USE

            While therapeutic benefits of cannabis have been shown in the literature, it’s use is not for everyone. Some may not prefer to use it or may be unable to ingest or tolerate the drug. Regulatory limitations may prevent the use of cannabis, or other comorbidities may arise decreasing the likelihood of effective treatment. In these cases, alternatives can be explored which may act on similar pathways as the use of cannabis. Two will be briefly discussed in this article: spinal manipulation, and dry needling.

Dry needling (DN) is the insertion of thin monofilament needles into the skin to treat muscles, ligaments, tendons, subcutaneous fascia, scar tissue, peripheral nerves and neurovascular bundles for various musculoskeletal conditions.20 “DN activates opioid-based pain reduction, mediated by endogenous cannabinoids and the sympathetic nervous system, and non-opioid pain relief via serotonin and norepinephrine from the brain stem.”5  In the periphery, DN increases a number of opioids via the endocannabinoid system. The addition of electrical stimulation to DN mediates the anti-nociceptive and anti-inflammatory effects on CB1 and primarily CB2 receptors, almost synonymous with cannabis use.5 Finally, DN stimulates the release of endogenous anandamide creating further release of endogenous opioids, and further stimulating the same CB2 receptors that cannabidiol (CBD) acts on.5,21,22 Electro dry needing also activates the sympathetic nervous system which when working with the endocannabinoid system helps to reduce pain and inflammation.5,21,22

 Like dry needling, the use of spinal manipulation may be an alternative to those who cannot or will not use cannabis. Endogenous cannabinoids have been suggested to contribute to short-term pain relief following spinal manipulation.23 A study by McPartland et al. found serum anandamide levels increased 168% 20 minutes following osteopathic manipulative treatment.23,24 Martins et al. found improvement in mechanical hypersensitivity and pain in mice following ankle mobilization/manipulation after injury, mediated by central and peripheral endocannabinoid pathways.25

In an emerging healthcare world, the use of cannabis and cannabis infused products is growing. Practitioners have an ethical obligation to be educated on effects of cannabis, potential benefits, or harms, and be able to recognize the patient who may be medically or recreationally using the drug. Healthcare practitioners should talk to patients about cannabis use in a nonjudgmental way to get the most accurate information to help guide care. Finally, practitioners should be aware of alternatives to cannabis use, including dry needling and spinal manipulation, which likely act using the same mechanisms of cannabis without the potential adverse reactions or dosing concerns.

Until next time,

Dr. Konstantinos Mavropoulos PT, DPT, FAAOMPT, Cert SMT, Cert. DN, Dip. Osteopractic, TPI Medical Level 2