Since cannabis legalization came into effect in Canada, there is an increasing number of companies selling cannabis-based products for pets. The majority of these products are derived from hemp, the fibrous form of the Cannabis sativa plant. In comparison to other varietals of cannabis, hemp contains higher concentrations of cannabidiol (CBD) and must contain less than 0.3% THC.
CBD is the compound most sought after by pet owners. It is one of over a hundred cannabinoid compounds that naturally occur in cannabis1 2. CBD is non-intoxicating, meaning it does not produce the “high” that is associated with THC.
In humans, cannabinoids have been approved to treat a variety of conditions that include AIDS-related anorexia, nausea and vomiting associated with chemotherapy, epilepsy, and pain related to cancer or multiple sclerosis. There is also clinical evidence that cannabinoids have the potential to treat other conditions, such as anxiety, depression, inflammation and cancer3 4.
How Do Cannabinoids Affect Pets?
In veterinary medicine, there are a limited number of studies on the effects of cannabinoids in pets such as cats and dogs. In humans, we know that cannabinoids interact with endocannabinoid receptors in the body’s central and peripheral nervous system to control a wide range of important bodily functions.
Learn More: A Medical Introduction to the Endocannabinoid System
Dogs have more endocannabinoid receptors in their brains than humans, which makes researchers suspect that dogs might more sensitive to the effects of cannabinoids than we are5. One thing that is clear is that THC, the psychoactive compound in cannabis, is toxic to dogs and cats. The majority of research so far has focused on these toxic effects6. The most common cause of cannabis poisoning comes from pets ingesting the owner’s supply—most commonly edible products, like cannabis-infused cookies, or plant material7.
Clinical signs of intoxication from THC include depression, increased production of saliva, dilation of the pupils, uncontrolled movement of the limbs, vomiting, urinary incontinence, tremors, hypothermia and decreased heart rate8. Higher doses may also cause problems with vision, agitation, rapid breathing, an increased heart rate, problems with the nervous system, hyperexcitability and seizures. The smallest lethal dose is 3 grams of cannabis plant material per kilogram of the pet’s weight9.
Death from THC intoxication is rare in animals. However, pet owners should be aware of the symptoms above and consult a veterinarian immediately if they think THC poisoning has occurred. Treatment for THC poisoning typically consists of close observation, hydration and ensuring the animal’s comfort while their body processes the material.
While THC is toxic to dogs and cats, clinical studies on CBD for dogs have shown so far that isolated CBD is considered safe10 11.
Therapeutic Potential of CBD in Pets
While there have not been many rigorous studies yet on CBD for pets, many pet owners report that they have successfully used CBD to treat symptoms of arthritis, epilepsy and anxiety in their furry companions12 13.
One of the few studies examining the benefits of CBD for dogs suggests that CBD can increase the comfort and activity levels of dogs suffering from osteoarthritis (OA). Dogs that received CBD oil (2mg/kg) every 12 hours for 4 weeks had significantly less pain and increased activity compared to dogs that received a placebo treatment14.
CBD may also have the potential to treat epilepsy, which is the most common chronic neurological disorder in dogs15. Preliminary results from a study at Colorado State University show that CBD can reduce the frequency of seizures in dogs suffering from epilepsy16.
Due to the limited number of studies conducted in cats and dogs, the best evidence for the therapeutic potential of CBD comes from human studies, where there is evidence that CBD can treat pain and inflammation from diseases other than arthritis and also relieve anxiety.
Learn More: A Medical Introduction to CBD
Risks of Using CBD in Pets
Pet owners should use caution when considering CBD-based products to treat their pet. Unlike medical cannabis products for humans, which are produced under strict regulatory conditions for safety and quality, pet-oriented cannabis products have no such regulation. In addition, there are currently no products approved by Health Canada for use in animals.
While CBD appears to be safe for pets, many veterinarian doctors are hesitant to recommend it for two reasons: one, because there are no rigorous scientific studies to confirm the safety and effectiveness of CBD for pets; and two, because the quality of these products is not guaranteed. A 2015 review by the U.S. Food and Drug Administration of various CBD products for pets found that some products did not contain the CBD concentrations indicated on the label or were contaminated with unlabeled concentrations of THC17, which is toxic to cats and dogs18.
How to Choose a CBD Product
When choosing a CBD-based product for a pet, owners should look for products that have undergone third-party testing. This will should confirm the actual CBD concentration in the product and whether or not THC is present.
CBD Dosing
While no therapeutic guidelines exist for dosing CBD for pets, it is recommended that owners follow the “start low, go slow” principle and keep a journal of the doses they give to their pet and the reactions they observe19. The easiest way to control CBD dosage is using a CBD oil, rather than an edible product because ingested products result in uneven and slow absorption into the body20.
Summary
With the legalization of cannabis in Canada, more and more pet owners are looking to explore the therapeutic potential of this ancient plant. While scientific evidence is limited, preliminary studies have so far shown that CBD seems to be safe for dogs, and may have therapeutic potential to treat epileptic seizures and symptoms of osteoarthritis.
Pet owners should use caution when using CBD products; however, since they are currently unregulated and not approved by Health Canada for use in animals. Unregulated CBD products have been found sometimes to contain THC, which is toxic to dogs and cats.
More research into the safety and effectiveness of CBD as a treatment for pets is needed, but some owners may find that with a third-party tested product, CBD could be an effective treatment for their beloved companions.
References
[1] Aizpurua-Olaizola O, Elezgarai I, Rico-Barrio I, Zarandona I, Etxebarria N, Usobiaga A. Targeting the endocannabinoid system: future therapeutic strategies. Drug Discov Today. 2017;22(1):105-110.
[2] Morales P, Hurst DP, Reggio PH. Molecular Targets of the Phytocannabinoids: A Complex Picture. Prog Chem Org Nat Prod. 2017;103:103-131.
[3] Abrams DI. The therapeutic effects of Cannabis and cannabinoids: An update from the National Academies of Sciences, Engineering and Medicine report. Eur J Intern Med. 2018;49:7-11.
[4] Whiting PF, Wolff RF, Deshpande S, et al. Cannabinoids for medical use: A systematic review and meta-analysis. JAMA. 2015;313(24):2456-2473.
[5] Fitzgerald KT, Bronstein AC, Newquist KL. Marijuana Poisoning. Topics in Companion Animal Medicine. 2013;28(1):8-12.
[6] Brutlag A, Hommerding H. Toxicology of Marijuana, Synthetic Cannabinoids, and Cannabidiol in Dogs and Cats. Veterinary Clinics of North America: Small Animal Practice. 2018;48(6):1087-1102.
[7] Fitzgerald KT, Bronstein AC, Newquist KL. Marijuana Poisoning. Topics in Companion Animal Medicine. 2013;28(1):8-12.
[8] Fitzgerald KT, Bronstein AC, Newquist KL. Marijuana Poisoning. Topics in Companion Animal Medicine. 2013;28(1):8-12.
[9] Fitzgerald KT, Bronstein AC, Newquist KL. Marijuana Poisoning. Topics in Companion Animal Medicine. 2013;28(1):8-12.
[10] Bartner LR, McGrath S, Rao S, Hyatt LK, Wittenburg LA. Pharmacokinetics of cannabidiol administered by 3 delivery methods at 2 different dosages to healthy dogs. Canadian Journal of Veterinary Research. 2018;82(3):178-183.
[11] Gamble LJ, Boesch JM, Frye CW, et al. Pharmacokinetics, Safety, and Clinical Efficacy of Cannabidiol Treatment in Osteoarthritic Dogs. Front Vet Sci. 2018;5:165.
[12] Pettanicals. Testimonials. 2018; https://pettanicals.ca/testimonials/. Accessed February 11, 2019.
[13] Berk BA, Packer RMA, Law TH, Volk HA. Investigating owner use of dietary supplements in dogs with idiopathic epilepsy. Research in Veterinary Science. 2018;119:276-284.
[14] Gamble LJ, Boesch JM, Frye CW, et al. Pharmacokinetics, Safety, and Clinical Efficacy of Cannabidiol Treatment in Osteoarthritic Dogs. Front Vet Sci. 2018;5:165.
[15] Kearsley-Fleet L, O'Neill DG, Volk HA, Church DB, Brodbelt DC. Prevalence and risk factors for canine epilepsy of unknown origin in the UK. Vet Rec. 2013;172(13):338.
[16] Guiden M. Preliminary data from CBD clinical trials' promising'. College News: News from the College of Veterinary Medicine and Biomedical Sciences2018.
[17] U.S. Food & Drug Administration. Warning Letters and Test Results for Cannabidiol-Related Products. 2015; https://www.fda.gov/NewsEvents/PublicHealthFocus/ucm484109.htm. Accessed February 7, 2019.
[18] Brutlag A, Hommerding H. Toxicology of Marijuana, Synthetic Cannabinoids, and Cannabidiol in Dogs and Cats. Veterinary Clinics of North America: Small Animal Practice. 2018;48(6):1087-1102.
[19] Canadian Association of Veterinary Cannabinoid Medicine. Treatment Dosing & Monitoring. 2018; https://www.cavcm.com/resources-for-pet-families. Accessed February 7, 2018.
[20] Fitzgerald KT, Bronstein AC, Newquist KL. Marijuana Poisoning. Topics in Companion Animal Medicine. 2013;28(1):8-12.