Tolerability of long-term cannabidiol supplementation to healthy adult dogs

Pharmacokinetic Characteristics of a Single Cannabidiol Dose in Oil and Treat Forms and Health Impacts After 30 Days of Administration in Dogs

Cannabidiol (CBD) has garnered significant interest in veterinary therapeutics, yet the pharmacokinetic and safety profiles of its various formulations remain incompletely characterized. This study compared the pharmacokinetics (PK) and health effects of CBD administered as oil (OG, 5 mg/kg) and treats (TG, 50 mg) in 16 healthy mixed-breed dogs over 30 days. Plasma CBD concentrations were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS), and the PK parameters were analyzed using non-compartmental methods. The CBD-infused rice bran oil formulation (OG) achieved a significantly higher dose-normalized maximum plasma concentration (Cmax, 58.40 vs. 21.29 kg·ng/mL/mg) and area under the curve (AUC0-inf, 305.85 vs. 141.75 h·kg·ng/mL/mg) compared to the treats (TG). The treat formulation exhibited relative reductions in bioavailability, with AUC and Cmax values approximately 2.2- and 2.7-fold lower than the oil group. The terminal half-life (~9.66 h OG vs. 8.52 h TG) and time to peak (2.38 h OG vs. 3.63 h TG) did not differ significantly. CBD accumulation occurred with repeated dosing but declined rapidly post-cessation. The hematological and biochemical analyses revealed no clinically adverse effects, though minor erythrocyte and eosinophil fluctuations were noted. The oil formulation demonstrated superior absorption, while both forms were well-tolerated. These findings highlight the impact of formulation on CBD absorption and support further research into optimized delivery methods for veterinary applications.

Pharmacokinetics of cannabidiol, (-)-trans-Δ9-tetrahydrocannabinol, and their oxidative metabolites after intravenous and oral administration of a cannabidiol-dominant full-spectrum hemp product to beagle dogs

Introduction

This study investigated the pharmacokinetics, safety, and tolerability of a full-spectrum CBD-dominant oil formulated in medium-chain triglycerides (MCT oil) after a single intravenous (IV) administration, a single oral (PO) administration, and multiple oral administrations of CBD at a dose of 2.2 mg/kg in adult male and female beagle dogs.

Methods

The CBD-dominant extract was administered to adult, intact beagle dogs (male n = 4, female n = 2) once intravenously, once orally, and every 12 h orally for 21 days at a dose of 2.2 mg CBD/kg body weight (BW). Blood samples were collected at predetermined times to measure concentrations of serum CBD, 7-hydroxy-CBD (7-OH-CBD), 7-nor-7-carboxy-CBD (7-COOH-CBD), Δ9-tetrahydrocannabinol (Δ9-THC), 11-hydroxy-THC (11-OH-THC), and 11-carboxy-THC (11-COOH-THC). Serum CBD and Δ9-THC concentrations were analyzed to estimate various pharmacokinetic parameters. Selected physical, behavioral, hematologic, and blood chemical measurements were obtained before and during single and repeated dose administrations.

Results

Pharmacokinetics of CBD after IV administration indicated a median (range) systemic clearance (CL) of 7.06 (6.14-10.5) mL/min/kg, a steady-state volume of distribution (Vss) of 2.13 (1.10-2.85) L/kg, and a half-life of 291 (183-508) min. The median (range) extent of systemic availability of CBD after a single oral dose was 31.2 (17.7-35.7)%. Pharmacokinetics of Δ9-THC after IV administration were characterized by a CL of 8.85 (6.88-14.4) mL/min/kg, Vss of 1.98 (1.30-2.30) L/kg, and a half-life of 169 (139-476) min. The extent of systemic availability of Δ9-THC after PO administration was 40.9 (20.5-46.2)%. The test article was well tolerated in all dogs during the study. Although serum alkaline phosphatase concentrations increased during the repeated PO dose study, they remained within normal limits.

Discussion

Both CBD and Δ9-THC were rapidly cleared after IV administration and exhibited extensive volumes of distribution. Comparison of clearance to serum hepatic blood flow estimated the hepatic extraction ratio and extent of first pass metabolism after PO administration, which was confirmed by analyzing the single PO dose pharmacokinetic data. The AUC0-∞ for 7-OH-CBD after single IV compared to single PO dose was not different, suggesting complete absorption of CBD from the formulation in MCT oil when administered with canned dog food.

The Potential of Cannabidiol for Treating Canine Atopic Dermatitis

Atopic dermatitis is prevalent in humans (hAD) and dogs (cAD) and profoundly impacts the patients' quality of life. The increasing number of new drugs in development for atopic dermatitis indicates both the need and potential for precision medicine to generate an optimised benefit-risk therapeutic plan. Cannabidiol (CBD), known for its potential anti-inflammatory and antipruritic properties, shows promise in hAD and cAD management, prompting the exploration of cannabinoids (CBs) and CBD as therapeutic tools. In fact, encouraging results on the benefits of using CBD in cAD have been published, along with safety evaluations that reveal that CBD is generally well tolerated in dogs. However, limited placebo-controlled trials and dosage variations in dogs pose barriers that hinder definitive conclusions. Challenges in product stability, inconsistent formulations, and legal ambiguities highlight the need for standardised CBD-based products for both research and commercial uses. The complex legal landscape further complicates accessibility and regulation. Despite these challenges, CBD is emerging as a potential avenue for cAD management, urging further high-quality research, standardised formulations, and legal clarity. This brief review provides valuable insights into the therapeutic potential of CBs and CBD in cAD, compared to hAD, emphasising the importance of rigorous research and unambiguous regulation for successful integration into veterinary dermatology.

CBD for pets: navigating quality assurance, safety standards, and marketing strategies

As the human cannabinoid (CBD) market grows, there is an inevitable transfer of the same or similar products into the veterinary sector. Advances in veterinary medicine and care of companion animals has led to extended life expectancy and consequently, there is an increased incidence of age-related chronic conditions that compromise quality of life. CBD products may alleviate these conditions. Research into CBD for companion animal species is on the rise, however, we found that there are no licensed veterinary CBD products available in the market due to a lack of appropriate testing and/or data. Here we outline the data that is available and show that the regulatory, and safety considerations around these products needs further consideration and this encompasses many products currently available on the market. Changes in regulations and further research for quality assurance are paramount to distribution of safe and applicable products for companion animals.

Investigation of the in vitro effects of cannabidiol, cannabidiolic acid, and the terpene β-caryophyllene on lymphocytes harvested from atopic and healthy dogs: A preliminary study

Cannabidiol (CBD) has been shown to have anti-inflammatory and antipruritic properties without the significant psychoactive effects. This study aims to evaluate the cytotoxic effects of, and the production of cytokines after exposure to CBD, cannabidiolic acid (CBDA), and β-caryophyllene (BCP), alone and in combination, by peripheral blood mononuclear cells (PBMC) from healthy and atopic dogs. Six healthy and five atopic, privately-owned dogs were enrolled. Peripheral blood mononuclear cells were harvested and incubated for 24 h with different concentrations of CBD, CBDA, and BCP alone or in combination. Cell viability and inflammatory cytokines were assessed. There was no difference in cell viability between baseline and tested concentrations of CBD, CBDA, or BCP in either healthy or in atopic PBMC. There was no effect of CBD, CBDA and BCP on the secretion of cytokines compared to baseline in healthy or atopic PMBC. The only exception was interleukin (IL)-10, increased in healthy PMBC exposed to CBD 100 ng/mL (p = 0.031) or CBDA 600 ng/mL (p = 0.017). Tumor necrosis factor (TNF)-α, monocyte chemoattractant protein (MCP-1), IL-2, and IL-18 were higher in atopic PBMC exposed to combinations of CBD, CBDA, and BCP compared to healthy post-exposure PBMC. This is the first study that tested the effect of CBD, CBDA, and BCP at different concentrations on atopic and healthy canine PBMC. The results of this study show that CBD, CBDA and BCP, at the tested concentrations, are safe for canine PBMC. However, CBD, CBDA and BCP did not show any direct anti-inflammatory effect under these experimental conditions. Further research is needed to confirm these results in a larger canine population.

Endocannabinoid system and phytocannabinoids in the main species of veterinary interest: a comparative review

Since the discovery of the endocannabinoid system and due to the empirical evidence of the therapeutic effects on several illnesses both in humans and animals that follow the administration of exogenous cannabinoids (i.e., phytocannabinoids), numerous studies have been conducted. These investigations aimed to identify the expression and distribution of cannabinoid receptors in healthy and pathologic organs and tissues of different animal species and to define the interactions of phytocannabinoids with these receptors. In the last decade, pharmacokinetics, efficacy and tolerability of many Cannabis derivatives formulations, mainly containing cannabidiol, in the main species of veterinary interest, have been also investigated. This manuscript summarizes the findings reported by the scientific studies published so far on the molecular mode of action of the main phytocannabinoids, the localization of cannabinoid receptors in organs and tissues, as well as the pharmacokinetics, efficacy and tolerability of Cannabis derivatives in dogs, cats, horses and other species of veterinary interest. A deep knowledge of these issues is crucial for the use of phytocannabinoids for therapeutic purposes in animal species.

Evaluation of the effect of cannabidiol administration with and without nonsteroidal anti-inflammatory drugs in dogs with mobility disorders: a prospective, double-blind, crossover, placebo-controlled study

Introduction

With rapidly growing interest in the use of cannabidiol (CBD) in the management of pain and other conditions, more information is needed on the safety and efficacy of this supplement, particularly its co-administration with commonly used pharmaceuticals such as non-steroidal anti-inflammatory drugs (NSAIDs). This study sought to assess the effect of CBD in dogs with mobility impairments, as well as evaluate the clinical tolerance of CBD used together with NSAIDs.

Materials and methods

Forty-two client-owned dogs with diagnosed mobility impairments were enrolled in this prospective, double-blind, crossover, placebo-controlled study. Baseline data were collected for 10-14 days followed by random allocation to either placebo or CBD oil for 45 days with a 30-day washout period in between. CBD was dosed at 5 mg/kg orally every 12 h with masked placebo administered at equal volume. Outcome measures included objective gait analysis, accelerometry, and clinical metrology instruments. CBD plasma levels and serum biochemistry were also collected along with hepatic ultrasound if warranted.

Results

Thirty-eight dogs finished the study with thirty-nine included for at least partial analysis. Compared to baseline, dogs receiving CBD showed evidence of improved outcomes based on blinded veterinary assessments and accelerometer data. Compared to placebo, dogs receiving CBD showed some evidence of improved outcomes on CBPI, CSOM, and blinded veterinary assessments, but not for objective outcome measures. There was evidence of increased ALP when CBD was co-administered with NSAIDs compared to CBD administration alone. Additionally, there was evidence of ALT elevations with CBD and NSAID co-administration, but this elevation did not show evidence of an increase over CBD use alone.

Discussion

These results suggest a potential therapeutic benefit in the administration of CBD for the management of mobility impairments, but greater ALP elevations were seen when administered with NSAIDs. While the sample size of dogs that received further hepatic work-up for liver enzyme elevations is small, chosen diagnostics varied, and liver biopsies were not performed, there did not appear to be clinically apparent liver damage. Further research is needed to better understand the efficacy of CBD in a larger population of dogs and patient tolerance and safety when administered with NSAIDs or other medications long term.

Tolerability of 2 and 4 mg/kg Dosing Every 12 Hour of a Cannabidiol- and Cannabidiolic Acid-Rich Hemp Extract on Mixed-Breed Dogs Utilized for Teaching in a Closed Colony

With the increase in popularity of utilizing cannabidiol (CBD) for human ailments, owners are actively interested in the possible utilization of cannabinoid products for their pets. The evaluation of CBD-rich hemp as an anti-anxiolytic, anti-inflammatory, immunomodulator, and anti-epileptic supplement has been assessed in previous studies in dogs, with adverse events such as ataxia or lethargy noted. In this study, the utilization of CBD-rich hemp was assessed at two concentrations to ascertain the impact on behavior as well as the tolerability of the medication given in a typically recommended dose and then twice that dose. Eighteen dogs were utilized in a randomized, double-blinded, placebo-controlled, 3 × 3 designed study. Each group of six dogs was provided placebo, 2 mg/kg, and 4 mg/kg of a cannabidiol/cannabidiolic acid (CBD/CBDA)-rich hemp in two-week intervals with one-week washout periods between each treatment period. Throughout the 10-week treatment period, student evaluations were performed, simulating clients' subjective assessments. Improvements in anxiety-related behavior and adverse events related to lethargy and ataxia were not observed and may indicate that the utilization of CBD-rich hemp products for behavioral changes may require higher dosing to mitigate unwanted behaviors in normal, healthy dogs. Furthermore, serum chemistry and serum cortisol were evaluated after each treatment period showing only a mildly significant increase in serum alkaline phosphatase when dosing at 4 mg/kg every 12 h, which is consistent with previously reported CBD dosing at these higher concentrations. Adverse events associated with CBD/CBDA-rich hemp extract given at 2 and 4 mg/kg every 12 h for two weeks were not reported, suggesting that using CBD-rich hemp in young, healthy dogs was safe during two weeks of treatment.

Healthy cats tolerate long-term daily feeding of Cannabidiol

Cannabidiol (CBD)-containing products are widely commercially available for companion animals, mirroring popularity in human use. Although data on the safety and efficacy of long-term oral supplementation are increasing in dogs, evidence remains lacking in cats. The purpose of these studies was to address gaps in the knowledge around the long-term suitability and tolerance of a tetrahydrocannabinol (THC)-free CBD distillate in clinically healthy cats. The studies were randomized, blinded, and placebo-controlled. The first study supplemented cats with either a placebo oil (n = 10) or with 4 mg/kg body weight (BW) CBD in placebo oil (n = 9) daily, with a meal, for 4 weeks. The concentration of CBD in plasma was measured over 4 h at d0 (first dose) and again at d14 (after 2 weeks of daily dosing). The second study supplemented cats daily with either placebo oil (n = 10) or 4 mg/kg BW CBD in placebo oil (n = 10) for a period of 26 weeks. A comprehensive suite of physiological health measures was performed throughout the study at baseline (week 0) and after 4, 10, 18, and 26 weeks of feeding, followed by a 4-week washout sample (week 30). Postprandial plasma CBD time course data, at both d0 and d14, showed a peak plasma CBD concentration at 2 h after the dose. This peak was 251 (95% CI: 108.7, 393.4) and 431 (95% CI, 288.7, 573.4) ng/mL CBD at d0 and d14, respectively, and the area under the curve concentration was higher by 91.5 (95% CI, 33.1, 149.9) ng-h/mL after 2 weeks of supplementation (p = 0.002). While in the first study the CBD group displayed increased alanine aminotransferase (ALT; 68.7 (95% CI, 43.23, 109.2) U/L) at week 4 compared to the placebo control group [1.44-fold increase (95% CI, 0.813, 2.54)], statistical equivalence (at 2-fold limits) was found for ALT across the duration of the second, long-term study. All other biochemistry and hematology data showed no clinically significant differences between supplement groups. Data presented here suggest that a THC-free, CBD distillate fed at a dose of 4 mg/kg BW was absorbed into plasma and well tolerated by healthy cats when supplemented over a period of 26 weeks.