Pharmacokinetics, efficacy, and safety of cannabidiol in dogs: an update of current knowledge

Abstract

In the last 5 years, interest has grown in using phytocannabinoids, particularly cannabidiol (CBD), in veterinary medicine to treat several pathologies, including pain, epilepsy, anxiety, nausea, anorexia, skin lesions, and even some types of cancer, among others. Indeed, due to a positive perception of CBD use, many pet owners are increasingly requesting this option to relieve their pets, and many veterinarians are exploring this possibility for their patients. Besides the widespread empiric use of CBD in pets, the research is trying to obtain proof of its efficacy and lack of adverse effects and to know its pharmacokinetics to define an appropriate posology. This review summarizes all data published so far about the canine pharmacokinetics, efficacy, and tolerability of CBD and cannabidiolic acid (CBDA). Despite a certain number of available pharmacokinetic studies, the kinetic profile of CBD has yet to be fully known, probably because of the very different experimental conditions. In terms of efficacy, most studies have tested CBD’ ability to relieve osteoarthritic pain. In contrast, few studies have evaluated its role in epilepsy, behavioral disorders, and skin lesions. From obtained results, some evidence exists supporting the beneficial role of CBD. Nevertheless, the limited number of published studies and the occurrence of bias in almost all require caution in interpreting findings. From tolerability studies, CBD’ side effects can be classified as mild or unremarkable. However, studies were prevalently focused on short- to medium-term treatment, while CBD is usually employed for long-term treatment. Further studies are warranted to define better whether CBD could be a valid adjunct in canine treatment.

Pharmacokinetics behavior of four cannabidiol preparations following single oral administration in dogs

“…Cannabis use is of interest not only in human medicine, but also in veterinary medicine, where extensive research is warranted to better understand the behavior and impact of the drug after administration in animals, since interspecies differences are a main factor influencing PK variation ( 27 ). Dogs have been the main companion animal species studied; however, the published PK studies have mainly been on oil-based CBD ( 11 , 15 , 28 ).…”

“…It is known that CBD is a lipophilic compound with limited absorption into circulating blood ( 12 ). Several reports on the PK of CBD in dogs have studied CBD in oil-based formulations, microencapsulated-beads, chewable soft capsules, and soft gel capsules ( 11 , 15–18 ). However, comparison data of oral CBD profiles in companion animals with different formulations are scarce.…”

“…Despite CBD having substantial therapeutic potential in animals, its pharmacokinetics (PK) profiles in companion animals, especially dogs, have yet to be clearly described ( 11 ). CBD is a chemically lipophilic molecule with poor and variable absorption ( 12 ).…”

“…Several dosage forms of CBD have been studied in animals ( 11 ), such as liquid oil-based, capsules, soft chew ( 15–17 ), microencapsulated oil beads and transdermal cream ( 18 ), intranasal, and as a suppository ( 19 ). Nowadays, there are variety of CBD products available for pets, with growing consumption in the global market ( 11 , 20 ). CBD oil-based preparation is one of most common forms consumed orally by pets and its kinetics behavior has been studied ( 11 ).…”

“…Nowadays, there are variety of CBD products available for pets, with growing consumption in the global market ( 11 , 20 ). CBD oil-based preparation is one of most common forms consumed orally by pets and its kinetics behavior has been studied ( 11 ). However, the highly lipophilic property of oil-based products affects the CBD level for optimal biological effect, since it has low aqueous solubility and bioavailability.…”