Established and Evolving Science
A growing body of evidence exists for the use of cannabis as medicine for certain medical conditions.(1,2) The Endocannabinoid System (ECS) is an independent, endogenous system of cannabinoid receptors and ligands found throughout the body that is involved in many physiologic processes and was first described in the 1990’s.(3,4) It is comprised of: (a) at least two G-protein coupled receptors (CB1 and CB2), (b) endocannabinoids (anandamide and 2-AG) and (c) regulatory enzymes. CB1 receptors are in presynaptic terminals in the brain and regulate neurotransmitter release. They are also found in adipose, liver, pancreatic, skeletal and immune cells. They mediate numerous physiological processes, including cardiovascular function, energy homeostasis, and reproduction. The activation of CB1 receptors also affects cognition and memory, reward sensation and emotional behavior, sensory perception, motor control, pain modulation, and other functions. CB2 receptors are found primarily on B cells, T cells, and macrophages and signaling results in inhibition of immune cell activation and pro-inflammatory cytokine production. (5,6,7)
Phytocannabinoids are the naturally occurring chemical compounds found within the flowers of the cannabis plant. Most of the biological properties attributed to phytocannabinoids are dependent on their interactions with the ECS in humans. Currently, more than 70 different phytocannabinoids have been discovered, but only a few of the major ones have been characterized in depth, primarily delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). (8)
THC is a main bioactive component of cannabis and is the main psychoactive ingredient in the plant. THC appears to possess anti-inflammatory, analgesic, muscle relaxant, neuro-antioxidative, and anti-spasmodic activities. THC has demonstrated efficacy in treating neuropathic pain and in reducing muscle spasms. THC may also act as a neuroprotectant via various mechanisms, potentially playing a beneficial role in several neurodegenerative disorders such as ALS and Alzheimer’s. Forms of synthetic THC have been approved for treatment of chemotherapy induced nausea and vomiting and for AIDS related anorexia. (3,7)
CBD is the major non-psychotropic cannabinoid found in cannabis. CBD has been shown to antagonize the undesirable effects of THC, such as intoxication, sedation, and tachycardia, while enhancing the analgesic and anti-emetic properties of THC. CBD has been proposed to possess anticonvulsant, anti-inflammatory, anti-cancer and neuroprotective properties. 9,10 Clinical studies have demonstrated very promising results in various epilepsy syndromes. (11,12)
The efficacy of cannabis in pain syndromes, including cancer related pain and neuropathic pain, makes it a promising alternative or adjunct to opioids. A lethal overdose from cannabis and cannabinoids has not been documented, primarily because cannabinoid receptors, unlike opioid receptors, are not located in the brainstem areas controlling respiration. (13,14,15,16) The addictive potential of cannabinoids is considerably lower than that of other prescribed agents or substances of abuse. (14,15,16) In states that have legalized medical cannabis, opioid overdose mortality rates have decreased by about 25% in one year and by about 33% after 3-5 years. (17)
Federal Stance
The federal government allows states to regulate the use of cannabis within their territories. The U.S. Department of Justice (DOJ) has issued guidance to state level District Attorneys not to prosecute those who follow state law. Additionally, in August 2016, the 9th Circuit Court of Appeals ruled that the DOJ cannot expend funds to prosecute people who violate federal drug laws but are in compliance with state medical marijuana laws.
State Regulations
Starting January 3, 2017, medical cannabis may be ordered for individuals with any of the following conditions: cancer, epilepsy, glaucoma, HIV, AIDS, PTSD, ALS, Crohn’s disease, Parkinson’s disease, multiple sclerosis, or other debilitating medical conditions for which a physician believes that the medical use of marijuana would likely outweigh the potential health risks for a patient.
Physicians must complete an 8 hour CME course presented by the FMA and FOMA, maintain an active physician–patient relationship for three months preceding the order, and provide written consent. The order must include dosage, route of administration and cannot exceed a 45-day supply. Additionally, the ordering physician must submit a patient treatment plan to the University of Florida College of Pharmacy. Smoking is not allowed and there are restrictions on use in public places. (For more information visit http://flhealthsource.gov/ocu/).
Summary
The passage of medical cannabis legislation across the country has garnered a great deal of attention. It’s imperative for physicians to remain up to date on the latest clinical data and regulatory requirements to ensure patients receive accurate and helpful information and to implement best practices when incorporating cannabis into patient care.
