Studies in dogs with chronic pain associated with osteoarthritis showed an increase in level of activity in animals receiving CBD-rich food supplements. Epilepsy
From the results seen in humans with drugs such as Epidiolex and Sativex in scientific studies and reviews, it could be expected that CBD-based products would be helpful to manage seizures in dogs. However, despite the numerous case reports presented by veterinary neurologists supporting the benefits of CBD as adjunctive therapy, as of December 2020, published controlled studies have not shown a statistically significant decrease in the number of seizures across the groups receiving CBD. Further research in this area is required before any clear conclusion can be drawn. Pharmacokinetics
The oral bioavailability of CBD varies greatly across species and it is linked to the presentation and the time of administration. A 24-hour kinetic examination in dogs showed that the absorption of the cannabidiolic acid (CBDA) does occur, and that this molecule is absorbed least twice as well as CBD post oral ingestion.It was found that the major metabolites of CBD in humans (7-OH-CBD and 7-COOH-CBD) are not prevalent in dogs, while 6-OH-CBD was found to be the primary metabolite in dogs receiving a CBD-enriched cannabis-derived herbal extract, suggesting that canine and human CBD metabolic route might be somewhat different. Pharmacology
Pharmacodynamics
Cannabidiol has low affinity for the cannabinoid CB1 and CB2 receptors, although it acts as an antagonist of CB1/CB2 agonists, despite this low affinity. The core effect of antagonism of CB1 receptors is reduced binding affinity of THC and any of its related isomers.
A recent study using X-ray crystallography showed that CBD binds inside the sodium channel pore at a novel site at the interface of the fenestrations and the central hydrophobic cavity of the channel. Binding at this site blocks the transmembrane-spanning sodium ion translocation pathway, providing a molecular mechanism for channel inhibition, which could contribute to a reduced excitability. A small clinical trial reported that CBD partially inhibited the CYP2C-catalyzed hydroxylation of THC to 11-OH-THC. Little is known about potential drug interactions, but CBD mediates a decrease in clobazam metabolism. Veterinary medicine
Research
The number of research projects and scientific publications on cannabidiol and other cannabinoids in pets has surged in the late 2010s. As of December 2020, there are no hemp-derived, cannabinoid-rich registered veterinary medicinal products in any of the major regions (see Legal status across countries). In the US and other territories there are, however, numerous veterinary nutraceutical products available OTC. The lack of clarity in the regulations governing veterinary hemp food supplements allows for products of questionable quality to flood the market, which may pose a risk to the wellbeing of pets and owners. To understand better the benefits of CBD and associated compounds for the quality of life of animals, companies specialized in CBD products for animals have been funding research projects. Canine osteoarthritis
CBDs ability to help regulate the endocannabinoid system and reduce the release of excitatory neurotransmitters could result in a retrograde inhibitory signal that lessens chronic pain responses.