The clinical use of cannabidiol and cannabidiolic acid-rich hemp in veterinary medicine and lessons from human medicine

The endocannabinoid system (ECS) is an integral neuromodulatory system involved in neuronal development, synaptic plasticity, and homeostasis regarding immunity, as well as brain and other physiological functions such as anxiety, pain, metabolic regulation, and bone growth. Cannabis is a plant that contains exogenous cannabinoids, which have the potential for profound interplay within the ECS as enzymatic inhibitors or receptor-mediated interactions. Activation of cannabinoid receptors leads to various intracellular signaling processes that are involved in cellular functions, but those interactions are diverse due to different affinities of each cannabinoid with relevant receptors. Among the exogenous cannabinoids, cannabidiol (CBD) has drawn attention due to its potential anticancer, antiangiogenic, anti-inflammatory, and antiseizure properties using in vitro and in vivo models. Although scientific evidence is limited in dogs, there appears to be cautious optimism regarding the utilization of CBD in conjunction with other therapeutics for a range of disorders. This review will primarily focus on current scientific research on the efficacy of CBD on seizure, anxiety, osteoarthritis, and atopic dermatitis, following a brief discussion of endo- and exogenous cannabinoids, ECS, their molecular mechanism, and potential side effects in veterinary medicine. Cannabinoid pharmacology and pharmacokinetics will be addressed in the companion Currents in One Health by Schwark and Wakshlag, AJVR, May 2023.