CBD products for pets are increasingly marketed in a dark zone where they are promoted to help animal health, but basic data on safety and effectiveness are limited, write Suzette Smiley-Jewell and Pamela Lein , from the University of California at Davis. The pair warn of the lack of formal regulation of animal CBD products.
Horse, dog or cat owners in some countries have probably noticed the abundance of cannabinoid (CBD) products entering the market. Pet stores carry a variety of CBD-infused oils, edibles, topicals, and gels marketed to improve pain, anxiety, and/or immobility in dogs and cats. CBD products are offered to equine owners for the same reasons.
The market is driven by both legislative changes that allow the production and recreational/medical use of cannabis, as well as discoveries that CBD can help relieve chronic pain, nausea, seizures and ailments mood, sleep and diet in humans.
Surveys have revealed that pet owners who use cannabis products themselves are likely to purchase CBD products for their pets. As a result, the global CBD Pets Market was valued at USD 125 Million in 2020 and is projected to expand at a compound annual growth rate of 58.9% from 2021 to 2028.
However, controversy surrounds CBD animal products because there are no officially approved CBD veterinary drugs, conflicting laws, and limited scientific studies regarding therapeutic efficacy and safety in animals.
What is CBD?
CBD is a chemical found in flowering cannabis plants, which has been used for thousands of years in rope, fabric, paper, food, and medicine, both human and veterinary. Cannabis-sativa plants containing less than 0.3% by dry weight of tetrahydrocannabinol (THC) – the “high” chemical in marijuana – are legally defined as hemp in the United States and the European Union.
CBD is abundant in hemp and it is not psychotropic like THC. CBD interacts with the endocannabinoid system, a signaling system in vertebrates and invertebrates that influences key biological processes, such as inflammation, pain, sleep, mood, immunity, appetite, memory and brain development.
Cannabinoid receptors are found throughout the body and brain, although their distribution may vary by species. CBD not only interacts with cannabinoid receptors, but also with other receptors (i.e. serotonin) involved in anti-inflammation, pain reduction, depression, and anxiety.
Does CBD benefit animals?
Relieving pain, reducing inflammation and relieving anxiety were the top three reasons people gave for buying cannabis products for pets in surveys of cannabis product use and perception by dog owners in the United States and Canada. CBD pet product websites and owner forums espouse anecdotal evidence of the health benefits of CBD; however, the number of actual scientific studies on pets is very limited, although steadily increasing since hemp became legal in the US and EU.
Currently, there are only six published studies on CBD and pain relief in pets. All six studies were done in dogs with osteoarthritis, a common problem with age and high body weight. In five of the six studies, pain decreased and mobility improved. These consistent results are noteworthy because the studies varied by form of CBD (oil or edible), dose (0.3–4 mg/kg), dosing regimen (once or twice daily), and duration of treatment ( one to three months). Side effects were relatively minor (eg drowsiness or incoordination), although with longer use an increase in serum alkaline phosphatase, a marker of potential liver damage, was seen. Similar feline and equine studies have not been performed.
To date, there are no published clinical studies on CBD and inflammation in dogs and cats. However, because high performance horses are at increased risk of injury and inflammation, a well-controlled study of CBD metabolism and inflammation was conducted in thoroughbreds. Horses tolerated CBD well and changes were observed in inflammatory signaling pathways. Therefore, the authors suggest that further studies are warranted.
CBD animal products are heavily promoted as “providing a sense of calm”, “relieving anxiety”, and “reducing stress”. Although CBD has been shown to reduce anxiety in rats, mice, and humans, there are no published scientific studies to confirm that the same is true in pets. Of the two published studies on dogs, neither supports CBD as an anxiolytic – a drug to prevent or treat symptoms of anxiety. Dogs exposed to the sound of fireworks after being given CBD for seven days had no reduced anxiety, as indicated by their activity or cortisol levels, and shelter dogs given CBD had reduced aggression towards humans, but a similar response was observed in control dogs. To date, there are no clinical studies of the effects of CBD on anxiety in cats or horses.
There is also interest in using CBD to treat epilepsy in animals as CBD-based Epidiolex has been approved in Europe and North America to treat rare forms of human epilepsy. A reduction in seizure frequency was found in two studies of the antiepileptic efficacy of CBD, but the effect was inconsistent in all dogs.
Considerations: CBD Animal Products
Despite the high demand for CBD-based animal health products, they are not regulated or approved by the US Food and Drug Administration, European Medicines Agency or the Veterinary Medicines Directorate/Food Standards Agency of the United States. UK.
As such, veterinarians cannot offer advice to clients unless permitted by local laws.
For example, California state law allows veterinarians to discuss cannabis use with their clients, but other US states prohibit it. This can be frustrating for veterinarians and clients due to dosing, efficacy, and safety issues. For example, while CBD appears to be well tolerated by animals, it is not without side effects, including sedation, dizziness, confusion, excessive salivation, or licking.
There are also species differences, with dogs absorbing more and taking longer to eliminate CBD than cats, and overall bioavailability increasing with fatty foods or oil. The interactions of CBD with other prescribed veterinary drugs are not fully understood. The lack of product regulation was evident in a study of 29 over-the-counter CBD dog products, which found that only 10 had CBD concentrations between 90-110% of the label claim and two had dangerous levels of arsenic and lead. Other studies have found high levels of pesticides used in marijuana fields in CBD products.
Without formal regulation of CBD animal products, we are stuck in a murky area where CBD is promoted to help animal health, but basic data on safety and efficacy is limited to non-existent. Greater monitoring, increased studies, and greater freedom of client-veterinarian communication would help everyone, especially the pets we love.
Suzette Smiley-Jewell, PhD, is a science program manager at the University of California, Davis. His doctorate is in pharmacology and toxicology.
Pamela J. Lein, PhD, is a professor in the Department of Molecular Biosciences, part of the School of Veterinary Medicine at the University of California, Davis. She is also a member of the MIND Institute. She has a particular interest in neurotoxicology, behavioral physiology, cell physiology, molecular physiology and neurophysiology.