Therapeutic Use of Cannabidiol (CBD) for Equine?
Cannabidiol (CBD) is one of many cannabinoid compounds found in the cannabis plant. Cannabis includes three species: Cannabis sativa, Cannabis indica, and Cannabis ruderalis. “Hemp”, a variety of Cannabis Sativa, is the common name for cannabis that is cultivated not only for CBD products, but for other non-drug uses such as fiber for clothes, ropes, and paper. Hemp is not to be confused with marijuana, which includes all cannabis species and cultivated for high levels of the cannabinoid tetrahydrocannabinol (THC). THC is the cannabinoid responsible for the psychoactive effect that causes the user to feel ‘high’, and while both hemp and marijuana produce CBD and THC, only small amounts (typically <0.3%) of THC are found in hemp. CBD does not have the same psychoactive effects as THC.
CBD Supplementation and Uses
CBD supplements come in many different forms, and can be administered through various routes such as oral ingestion, inhalation, sublingual, rectal, or topical application to the skin. CBD products may be supplied as a CBD-only oil, a full-plant extract oil, dried plant, in liquids, creams, ointments, or capsules, among many other forms. Currently, these CBD products are aggressively marketed online and in print for the use in horses, making exaggerated and unproven health claims including the promise of chronic pain relief, reduction in anxiety and depression, lowering inflammation, increased neuroprotective properties (brain health), aiding gut health, treating seizures, and protecting against bone disease. The effects of CBD in horses is unknown! There are no studies or scientific research into the effect of CBD in horses.
The Industry Lacks Published Studies
Given the increasing interest of health claims associated with the therapeutic uses of CBD, more rigorous studies are needed to substantiate and validate these claims, as well as to understand the potential health risks associated with both short-term and long-term CBD use. In humans, CBD, THC, and other cannabinoids interact in the body as part of the endocannabinoid receptor system. Horses also have endocannabinoid receptors, so similar effects are possible, though it is unknown due to the lack of scientific data or published studies (pharmacodynamics). Additionally, there is no information on the equine metabolism (pharmacokinetics) of CBD, thus it is impossible to estimate or determine withdrawal times in horses.
Over the last several years, interest and research has focused on the potential therapeutic use of CBD. The US FDA (Food and Drug Administration) has approved a CBD drug, Epidiolex, for the treatment of two epilepsy disorders in humans. Only this CBD drug has a Schedule V classification, while all other CBD products remain a Federal Schedule I drug prohibited for any use. Many states have laws allowing medical use of cannabis and/or products that are high in CBD and low in THC (<0.3%) with varying degrees of restriction, so care must be taken to cross-reference state and local laws. Despite diverse regulation for human consumption, at present there are NO cannabidiol products approved for use in horses, and the Association of Racing Commissioners International (ARCI) has designated CBD as a penalty Class 3B drug and THC a Penalty Class 1A drug.
While the FDA-approved CBD drug Epidiolex is regulated for efficacy and is produced under good manufacturing practices (GMP) to ensure the safety, quality and sterility of the product, CBD products sold on the internet or at dispensaries are not manufactured to these same FDA and GMP standards. Though state laws and regulations for CBD supplements may require content labeling and quality manufacturing controls, they are inconsistent and sometimes nonexistent.
Artisanal (homemade) extracts and supplements are also not required to be tested CBD or THC content, or for parameters such as microbial safety, residual solvents, or contaminants such as pesticides and herbicides. How does one effectively use a product when there may be significant variance in production, content, and safety? Even though supplements are required to contain less than 0.3% THC, the small quantity found in hemp will ultimately be extracted and concentrated alongside the CBD. Without laboratory testing and labeling requirements of the finished product, THC may then be inadvertently ingested, and a positive finding for THC from a hemp-derived CBD product may occur. Since microbial testing is also not a regulated requirement, pathogens such as Salmonella, E.coli, Listeria, and consumption of other harmful compounds are a major concern. It is difficult, if not impossible, to know exactly what you are getting.
Unknown Side Effects of CBD Usage
Besides the health and safety concerns, there are noted side effects in humans such as diarrhea, changes in appetite, fatigue, drowsiness, light headedness and low blood pressure. Although the majority of the science indicates that CBD is safe for use, CBD may interact with the cytochrome P-450 system, an enzyme in the liver responsible for metabolizing most drugs and toxic compounds, which could result in either faster or slower metabolism times for other drugs. Other foods or supplements such as grapefruit, watercress, and St. John’s Wort have similar effect on the cytochrome P-450 system. Unwanted side effects and potentially an overdose could be the impact of CBD’s inhibition of the cytochrome P-450 system.
Due to the lack of regulation, unsubstantiated claims without published studies, and unknown health effects and potential side effects, be cautious of all of the CBD oil and supplement claims for novel pain relief, athlete performance and recovery statements. There are numerous dosage and safety concerns around these unregulated CBD supplement products, so using prescribed drugs from a licensed veterinarian to treat all equine health issues is the best approach in the care and welfare of your animal.