Many people are using medical marijuana and CBD products to help alleviate symptoms associated with a variety of conditions. With animals being a part of the family, it is only logical that many people would wonder, do CBD oil products have the same benefits for dogs as they do for humans? Are CBD and cannabis products safe for dogs?
The unfortunate fact is that very little research has been conducted in the realm of Cannabis sativa compounds and their effects on our pets. The reason for this? Obtaining approval and funding for research for pets is exceedingly difficult due to legal reasons.
While there has not been much research, there is still good information out there to help consumers understand more about the potential role of CBD in dogs.
Cannabidiol and the Endocannabinoid System
Many of the therapeutic benefits of medical marijuana and its compounds comes from the way phytocannabinoids found in marijuana react with our internal cannabinoid system, known as the endocannabinoid system (ECS).
Every animal with a backbone has an endocannabinoid system. This system is made up of endocannabinoids, their receptors, and enzymes that are involved in the biosynthesis and degradation of cannabinoids.
The Cannabis sativa plant has been used for thousands of years for the treatment of medical conditions, and it is largely thanks to the phytocannabinoids found in this plant and the way they interact with the ECS that it has these effects. (4)
Cannabis sativa is one species of plant that encapsulates both medical marijuana plants and industrial hemp plants. The main difference between the two when it comes to the therapeutic purposes is that marijuana plants have a higher concentration of THC (tetrahydrocannabinol) and hemp plants a higher concentration of CBD (cannabidiol).
The euphoria, or “high,” that one experiences if using marijuana is caused by the THC. CBD alone does not have this effect. The reason for this difference is how these cannabinoids work in the body.
The ECS has two cannabinoid receptors: CB1 and CB2 receptors. CBD1 receptors are found throughout the central nervous system and peripheral tissues, with a high concentration in the brain. CB2 receptors are found in our immune tissues and cells.
THC has a high affinity for CB1 receptors, leading to alterations in neurocognition, while CBD does not have a high affinity for either CB1 or CB2 receptors and interacts with the ECS and our bodies through a variety of different mechanisms.
THC, CBD, other cannabinoids found in cannabis and even synthetic cannabinoids have been found in studies to exert positive effects on those suffering from a wide variety of conditions.
In humans studies, cannabinoids have been found to exert therapeutic potential for those suffering from depression, arthritis, anxiety, Alzheimer’s disease, schizophrenia, pain disorders, multiple sclerosis, cancer, mood disorders, epilepsy, and headaches, among many others. (4)
Cannabidiol and Dogs
While there have been very few studies around the effects of cannabidiol in dogs, many dog owners have used CBD products have reported positive effects.
If future studies end up supporting these uses of CBD oil for dogs, it is likely due to the way CBD acts in the ECS of dogs.
It is important to note that interspecies differences in the effects of cannabinoids have been shown to exist, so although research on one species may be representative of a possible effect on another species, those results are not conclusive until further research has been done on the effects of CBD for specific conditions in each species.
One such difference that exists has to do with THC and toxicity. In humans there is no known dose of THC that is toxic, however in dogs there is a toxicity threshold. THC may become toxic for dogs if more than 3g/kg of body weight is consumed. (1)
Fortunately the studies thus far conducted on CBD and dogs have not reported any negative side effects or toxicity.
Thus far, on dogs specifically, there have been three studies carried out regarding cannabinoids and other agents that affect the ECS and the therapeutic potential: topical cannabidiol and its effect on glaucoma, PEA (palmitoylethanolamide) and dermatology, and an in vitro study on tumor growth inhibition by a synthetic cannabinoid agonist.
2% THC Eye Drop Solution May Help in Canine Glaucoma
In a 2013 study published in the American Journal of Veterinary Research, researchers sought out to examine the effect of topical CBD in the intraocular pressure (IOP) and aqueous humor flow rate (AHFR) of healthy dogs. (5)
In glaucoma, vision loss is related to damage caused by an increase in IOP, with the regulation of AHFR crucial in maintaining eye health.
12 normal dogs were randomized into either a 2% THC eye drop group or a placebo group and received eyedrops once every 12 hours for 9 doses, with IOP and AHFR measurements taken at multiple points.
They found that the mean IOPs were significantly decreased in the THC group but not with the control treatment, with no significant change in AHFRs for either group.
These findings suggest that THC may help to reduce IOP in normal dogs. As increased IOP is linked to vision damage in glaucoma patients, more research is needed to determine the efficacy of topical THC for dogs with glaucoma.
The Impact of PEA on Dermatology in Dogs
PEA is an endogenous fatty acid amide that has been tied to inflammation and chronic pain. PEO is not a classic endocannabinoid as it lacks affinity for the CB1 and CB2 receptors, however it has been found to enhance the activity of the endocannabinoid anandamide.
In a 2010 study published in Veterinary Immunology and Immunopathology, the effect of PEA in dermatological disorders with mast cell hyperactivity in dogs was examined.
The study found that PEA inhibited tumor necrosis factor, prostaglandin D2, and histamine levels induced by canine anti-IgE from mast cell skin biopsies taken from 18 dogs. (8)
In 2012, the same researchers examined the effect of PEA on cutaneous allergic inflammation in six beagles and found that PEA helped to reduce this inflammation. (9)
A Synthetic Cannabinoid Agonist Inhibits Tumor Growth in Canine Osteosarcoma Cells
In a 2013 study published in Veterinary Medicine: Research and Reports, researchers examined the effect of WIN-52,212-2, a synthetic cannabinoid agonist, on tumor growth. (10)
The researchers found that this cannabinoid agonist was successful at inhibiting tumor growth in canine osteosarcoma cell lines.
The very limited studies that have been conducted with dogs and cannabinoids or other drugs that affect the ECS have shown promising effects, however much more research needs to be conducted to confirm if CBD oil is helpful for the variety of therapeutic roles that have been found in human models and other animal models.
CBD Bioavailability in Dogs
It is likely that CBD products will impact each dog differently.
Two studies were conducted on the oral bioavailability of CBD and a dimethylheptyl homolog (DMH) of CBD in dogs. Both studies found that plasma levels of CBD and DMH CBD were not elevated for ½ of the dogs, however the other dogs did show an increase in plasma CBD. (12,13)
In the DMH CBD study the oral bioavailability found in the four of eight dogs with increased plasma levels were 3%, 21%, 39%, and 43%. (12)
In the CBD study the oral bioavailability of 180 mg of CBD found in the three of six dogs with increased plasma levels ranged from 13% to 19%. (13)
These studies demonstrate that the bioavailability of hemp oil products is likely to vary from one dog to the next. Because of this wide variation combined with very few studies that help with dosing, it is recommended to start at a low dose, build up, and closely monitor your dog’s response to the CBD product.
Do CBD Products Help Dogs?
We do know that dogs, just like humans, have an ECS, and that cannabinoids from Cannabis sativa are likely to affect the ECS. Exactly how effective different cannabinoids are and on what conditions is a question that has not yet been answered by scientists, leaving owners to test out products at their own discretion and monitor these results.
Online you will find many owners discussing benefits of CBD oil on pain, cancer, inflammation, anxiety, and many other conditions in dogs, and we will have to wait and see what studies in the future find.
Be sure to avoid products with THC due to the toxicity in dogs, however there are many products out there formulated specifically with dogs in mind that are rich in cannabidiol and have little to no THC.
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- Fischer KM, Ward DA, Hendrix DVH. Effects of a topically applied 2% delta-9-tetrahydrocannabinol ophthalmic solution on intraocular pressure and aqueous humor flow rate in clinically normal dogs. American Journal of Veterinary Research. 2013; 74: 275–280.
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- Cerrato S, Brazis P, Della Valle MF, et al. Effects of palmitoylethanolamide on the cutaneous allergic inflammatory response in Ascaris hypersensitive Beagle dogs. The Veterinary Journal. 2012; 191:377–382.
10 Figueiredo AS, Garcia-Crescioni HJ, Bulla SC, et al. Suppression of vascular endothelial growth factor expression by cannabinoids in a canine osteosarcoma cell line. Veterinary Medicine: Research and Reports. 2013; 4:31–34.
- Nolen RS. With pet owners already using the drug as medicine, veterinarians need to join the debate. Journal of the American Veterinary Medical Association. 2013; 242:1604–1609
- Samara E, Bialer M. Pharmacokinetics of the dimethylheptyl homolog of cannabidiol in dogs. Drug and Metabolism Disposition. 1988; 16(6):875-879
- Samara E, Bialer M, Mechoulam R. Pharmacokinetics of cannabidiol in dogs. Drug Metabolism and Disposition. 1988; 16(3):469-472