Patient Counseling Guidelines for the Use of Cannabis for the Treatment of Chemotherapy-Induced Nausea/Vomiting and Chronic Pain
Patrick Makary, Jayesh R. Parmar, Natalie Mims, Nile M. Khanfar and Robert A. Freeman
JOURNAL OF PAIN & PALLIATIVE CARE PHARMACOTHERAPY, 2019
The use of cannabis medications has grown in recent years for the symptomatic relief of chemotherapy-induced nausea/vomiting (CINV) and chronic pain (cancer-related and noncancer-related). As states legalize the use of cannabis, it is important for pharmacists and other health care professionals to beaware of how to counsel patients receiving prescriptions for cannabis medications. The aim of this study was to develop patient counseling guidelines for the use of cannabis products in treatment of CINV and chronic pain. A literature search was performed using Medline/PubMed resources and Google Scholar between July 2015 and August 2018 using broad search terms, e.g., cannabinoids adverse
effects, cannabis, natural cannabinoids, and tetrahydrocannabinol. Using the American Society of Health-System Pharmacists patient counseling guidelines and medical information on cannabis medications gathered from drug databases, a comprehensive counseling guideline was developed. Medical evidence of the use of natural cannabis medications that are smoked or orally ingested have not been studied as extensively as oral therapeutic agents currently available. Cannabis medications have become more prevalent by approval of legislators in several states. Hence, pharmacists and health care professionals should counsel patients effectively on its use. This guideline needs to be tested to assess its utility in patients.
KEYWORDS : Pain; cannabis; cannabidiol; counseling; chemotherapy; cancer
Interest in the use of cannabis medications, for example, synthetic cannabinoids (CesametVR and
MarinolVR ), natural cannabinoids (SativexVR ), and cannabis that is smoked or orally ingested, has grown in recent years as the prevalence of cancer increases and as patients desire additional options
for the symptomatic relief of chemotherapyinduced nausea/vomiting (CINV) and chronic pain (1). As a consequence, it is important that pharmacists and other health care professionals are aware of the underlying evidence about pharmacology, therapeutic uses, clinical points, safety, and drug–drug interactions surrounding its increasing use. Patient counseling guidelines are an important aspect of providing patients with objective information when utilizing any drug safely and effectively. The American Society of Health-System Pharmacists (ASHP) has developed step-by-step guidelines that provide health care providers with information that is relevant in the development of any patient counseling protocol (2). Cannabis medications are currently available in more than 50% of U.S. states including the District of Columbia in non-plant form for alleviating debilitating symptoms for a number of various conditions (3). Tetrahydrocannabinol (THC) is the active ingredient in natural cannabis
medications that cause the pharmacological effect of creating the “high” for which it is known.
However, cannabidiol (CBD) counteracts the psychotropic effect of THC. Also, the acid metabolite tetrahydrocannabinol carboxylic acid (THC-COOH) is responsible for the nonpsychotropic effects and is a promising potential candidate for clinical therapeutic use (4).
Cannabinoids are derived from three sources: (a) phytocannabinoids are cannabinoid compounds produced by the plants Cannabis sativa or Cannabis indica, and Cannabis ruderalis, native to Europe/Asia; (b) endocannabinoids are neurotransmitters produced in the brain or in peripheral tissues that act on cannabinoid receptors in the body; and (c) synthetic cannabinoids are synthesized in the laboratory and are structurally analogous to phytocannabinoids or endocannabinoids and act by similar biological mechanisms (5). Cannabis sativa is distinguishable from other species, for example Cannabis indica, based on many key attributes including height and stature of the plant, internodal length, leaf size and structure, bud size and density, flowering time, odor, smoking ability, and pharmacologic effects. Indica plants tend to grow shorter and bushier than the sativa plants. Indica strains tend to have wide, short leaves with short wide blades, whereas sativa strains have long leaves with thin long blades (6). Both of these species have been used to develop
medical cannabis preparations.
As cannabis medications continue to become a patient-driven treatment option, health care providers, especially pharmacists, must be updated with the ongoing changes with respect to its use for patient treatment (7). While a large number of states have currently legalized medical and recreational cannabis, there are currently very few states in the United States that allow pharmacists to dispense cannabis. As more states participate, it becomes inevitable that pharmacists should be knowledgeable about cannabis medications and have the ability to appropriately counsel patients in areas including efficacy expectations, side effects, proper administration, and interactions with other disease states and medications. However, there appears to be no proper guidelines on patient counseling in states with local dispensaries without pharmacists, leaving the physician as the only option for patient counseling (8). Hence, the purpose of this article is to develop a comprehensive counseling guideline that may be used by health care providers when educating patients regarding the use of cannabis products for the treatment of CINV and chronic pain.