Medicinal Cannabis

This module considers the cannabis plant and its rich and colourful history as a psychotropic agent, a commodity, a sacred entity, and a medicine to treat a raft of disorders. Maligned and criminalised in the second half of the 20th century, cannabis is now in a new cycle with a burgeoning and sustained scientific interest in its potential medical uses. The module also outlines the history behind the discovery of different cannabis strains, specific phytocannabinoids (e.g., THC), endocannabinoids (e.g., AEA) and the body’s innate endocannabinoid system, and the myriad of biological processes to which it is linked. Finally, the module looks at the discovery of terpenes, and with it, the so-called entourage effect or the synergism between the multitude of compounds within the whole plant.

This module analyses the homeostatic endocannabinoid system and its broad scope of influence in both health and disease. The endocannabinoid system’s three central instruments are established, the endocannabinoids, receptors, and enzymes, followed by an analysis of the system’s homeostatic functions, including analgesia, mood, energy balance, and stress coping. Evidence for the relationship between insufficiency or dysregulation of the endocannabinoid system and particular disorders is also discussed. Finally, the module provides an overview of our current understanding of cannabinoids, such as THC and CBD, and how ongoing research into targeted manipulation of the endocannabinoid system with active cannabinergic compounds may prove therapeutic in numerous pathological conditions.

This module provides a comprehensive examination of the two main cannabinoids, tetrahydrocannabinol (THC) and cannabidiol (CBD); it distinguishes between their main actions and analyses their synergistic relationship. Given that THC and CBD interact differently within the endocannabinoid system and with other neurotransmitters, the module considers their different therapeutic potential, bioavailability, metabolism, toxicology, and dosing. The module also describes the most up-to-date method of cannabis classification, or chemovars, a method based on chemical composition in order to match a specific profile to a particular treatment. For example, chemovars establish the CBD to THC ratio in a given ‘species’ as well as other cannabinoids involved in whole plant medicine, such as CBG, CBN, and CBC. They also determine the presence of other important constituents, such as a wide variety of terpenes.

This module discusses the safe use of medicinal cannabis, outlining the routes of administration, side effects, and contraindications. Cannabinoid pharmacokinetics are also examined, including its absorption following diverse administration routes, metabolism by different tissues and organs, bioavailability and elimination from the body. Despite its extreme safety as a medication generally and particularly relative to opioids, potential adverse effects and contrindicaitons of cannabis are outlined. The module also analyses the potential for drug-to-drug interaction given CBD and THC’s effects on common biological pathways implicated in drug metabolism via their interactions with cytochrome P450 enzymes specifically.

This module identifies a number of basic ailments that may be successfully treated with medical cannabis in General Practice. For example, the adverse effects of cancer treatment, the symptoms of chronic pain, anxiety, depression, and insomnia could be alleviated by medicinal cannabis with mild side effects and minimal risk of toxicity or addiction. Providing that conventional treatments have failed or caused unacceptable side effects, a growing number of conditions lend themselves to treatment with cannabis. Given the complex chemical profile, there is a single medication potential to assist with multiple symptoms, thereby reducing polypharmacy. The module applies an individualised management plan to three comprehensive case studies for patients with chronic pain, osteoarthritis, and anxiety and depression. Considerations ranging from the cost to the patient to the appropriate THC to CBD ratio are addressed. Finally, the module guides the practitioner in navigating an application for a TGA Special Access Scheme/SAS B.

This module discusses the use of medicinal cannabis as an emerging option for clinicians to reduce and alleviate difficult-to-treat, chronic, neuropathic pain. The module analyses the endocannabinoid system and the diverse, multimodal mechanisms of cannabinoid-induced analgesia. THC and CBD are an excellent additive treatment to concurrent conventional pain management for many chronic pain types associated with a range of diseases such as fibromyalgia, traumatic injury, and multiple sclerosis. For patients suffering from neuropathic pain, cannabinoids may be used successfully as an adjunctive, opioid-sparing, or ultimately a replacement therapy for managing their pain. The module also discusses a management plan’s necessary considerations (such as determining dosages and accounting for safety considerations) and applies these protocols to a chronic pain case study.

This module examines the homeostatic functions of the endocannabinoid system in relation to mood, stress response, and sleep. It also evaluates the therapeutic capacity of the major cannabinoids (THC and CBD), in isolation and in synergy, in relation to anxiety, depression, and insomnia. In developing a treatment plan, essential factors such as the interplay between depression, anxiety, pain, and insomnia are considered, as well as protocols for THC to CBD ratios in basic dosing, and the route and timing of administration with reference to each condition. With regard to treating insomnia particularly, the module addresses the role of other lesser-known cannabinoids, such as CBN, and terpenes. Pertinent considerations such as the dampening effect of CBD upon the undesirable effects of THC such as intoxication, tachycardia and psycho-activity (of particular importance when treating anxiety) are also discussed.

This module reviews the myriad of functions of cannabinoids and the endocannabinoid system and considers the supportive role they may have to play in cancer therapy. Although research continues into the anti-tumour properties of cannabinoids, there is currently no evidence that medical cannabis can cure or even treat cancer. Nonetheless, it can be a successful additional therapy used in the management of cancer symptoms and the iatrogenic effects of treatment. The judicious use of medicinal cannabis can significantly improve cancer sufferers’ quality of life by managing persistent symptoms and side effects such as, cancer pain, nausea, vomiting, and chemotherapy-induced nausea and vomiting. The module also considers the case studies of three different cancer patients and, for each, examines issues for the clinician related to assessment, dosing recommendations, formulation, methods of administration, and side effects.