Toxicology of Marijuana, Synthetic Cannabinoids, and Cannabidiol in Dogs and Cats

Case report: Treatment of non-medical tetrahydrocannabinol toxicosis with transmucosal cannabidiol-infused dissolving sheets in six dogs

Increased cases of canine tetrahydrocannabinol (THC) toxicosis have been reported in North America in recent years. Cases are often evaluated on an emergency basis and treatment has relied upon supportive care which can be costly and prohibitive for some pet owners. The purpose of this report is to describe the clinical findings and outcomes in dogs with non-medical, presumptive THC toxicosis treated by administration of a cannibidiol (CBD)-infused transmucosal dissolving sheet. Medical records of six cases of non-medical, presumptive THC toxicosis from a private primary care practice and a private after-hours emergency practice were reviewed and summarized. Five of six cases were treated exclusively with transmucosal CBD (0.4-2.6 mg/kg); one case also received injectable anti-emetic therapy. Lethargy and ataxia noticeably improved and all additional clinical signs resolved within 45 min of treatment in five of six cases. No further follow-up measures for THC toxicosis were required in any case; one case required additional follow-up for presumably unrelated gastrointestinal distress. This is the first report of treatment of canine THC toxicosis by administration of CBD. The use of transmucosal CBD-infused dissolving sheets resulted in expedient resolution of clinical signs in a minimally invasive manner that is accessible to both clients and veterinary practitioners.

Analysis of cannabinoids in plasma from 38 cases of suspected cannabinoid intoxication in dogs

OBJECTIVE

To quantify and characterize plasma cannabinoid concentrations in cases of suspected cannabis toxicity in dogs, identify potential correlations between clinical signs and plasma concentrations, and assess the specificity of cannabis toxicity diagnosis based on clinical signs alone.

DESIGN

Observational study.

SETTING

Veterinary teaching hospital.

ANIMALS

Thirty-eight client-owned animals.

INTERVENTIONS

Blood was collected from dogs presenting to the emergency room for suspected cannabinoid intoxication based on history or physical examination findings. Samples were analyzed using a validated liquid chromatography-tandem mass spectrometry method for the cannabinoids Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and their active metabolites.

MEASUREMENTS AND MAIN RESULTS

The most common abnormality observed was ataxia (35/38 dogs), with urinary incontinence, lethargy, and hyperesthesia also commonly noted. Cannabinoids were quantifiable in 37 of 38 plasma samples (97.4%), with THC the predominant cannabinoid (range: 1.99-2748 ng/mL). Lower concentrations of CBD (up to 115.3 ng/mL) and cannabinoid metabolites were detected. Of the clinical signs recorded, only abnormal reflexes were statistically correlated with the THC concentration at the time of sampling (P = 0.01).

CONCLUSIONS

A diagnosis of suspected cannabinoid toxicity based on case history and clinical presentation was confirmed via quantifiable plasma concentrations in nearly all cases. Although the range of plasma cannabinoid concentrations was broad, the clinical signs observed were generally similar. Other than the presence of abnormal reflexes, clinical signs were not associated with plasma THC concentrations. Subsequent confirmation of cannabinoids in plasma indicates that cannabis toxicity in dogs can be diagnosed with high specificity by veterinarians based only on history and clinical abnormalities.

Danish dog owners' use and the perceived effect of unlicensed cannabis products in dogs

The interest in the use of medical cannabis has increased in recent years in both human and veterinary fields. In Denmark, there are no veterinary-licensed medical cannabis or cannabinoid supplements, and it is illegal to prescribe or sell cannabinoids intended for the treatment of veterinary patients. This study aimed to explore the unlicensed cannabinoid use in Danish dogs, by questioning dog owners about usage, indication for use, way of purchase, and their perceived effect of the cannabinoid treatment. An anonymous online survey was distributed via social media. The total number of respondents were 2,002, of which 38% indicated using or having administered cannabinoids to their dog. The majority of the respondents confirming the use of cannabinoids (93%) had used cannabidiol drops/oil and only few (4%) reported using Δ9-tetrahydrocannabinol-based products. Most owners (67%) purchased the products online. The three most common indications for use were pain alleviation, behavioural issues, and allergy. When asked about the respondent-perceived effect the majority reported a good or very good effect. The indication with the highest percentage of owner-perceived positive effect (77%) was pain alleviation. This study shows that, despite no licensed veterinary cannabinoid products being available in Denmark, dog owners do supplement their dogs with cannabinoids and the majority of these perceive that the treatment had a positive effect. This supports the need for more evidence-based knowledge in veterinary cannabinoid therapy.

Placebo-Controlled Trial of Daily Oral Cannabidiol as Adjunctive Treatment for Cats with Chronic Gingivostomatitis

A placebo-controlled study evaluated the clinical efficacy and safety of a commercially available cannabidiol (CBD) oral formulation as an adjunctive treatment for pain management for feline chronic gingivostomatitis (FCGS). CBD was included in a multimodal treatment routinely performed on client-owned cats with FCGS that were submitted to dental extractions. Twenty-two cats were consecutively included in the study. The first group was treated using a fixed dosage of 4 mg per cat every 12 h for 15 consecutive days, and the second received a placebo of similar features. Treatments began 2 h before dental extractions. Pain and disease severity were assessed at days 0 and 15 using the Composite Oral Pain Scale (COPS-C/F) and the Stomatitis Disease Activity Index score (SDAI). Weight, vital and biochemistry parameters, and analgesic reinforcement needs were also registered at the same time points. In the treated cats, blood was collected after 4, 8, and 12 h to determine CBD serum concentrations using ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS/MS). After data analysis using mixed models, a significant improvement in the SDAI scores of cats medicated with CBD was found. The protocol is safe since severe adverse effects and biochemical changes were not observed during the treatment period. This study suggests that the cats benefited from this treatment.

New Synthetic Cannabinoid ADB-BUTINACA-Related Death of a Police Dog

The popularity of synthetic cannabinoids puts police sniffer dogs at risk of accidental introduction of such substances into the body. The extreme efficacy and potency of many new synthetic cannabinoids are associated with a high risk of serious poisonings and even deaths. The paper presents the toxicological findings in an intoxication of a police dog, in which a new synthetic cannabinoid ADB-BUTINACA was detected and quantified in postmortem materials. The screening analyses were performed by liquid chromatography with tandem mass spectrometry (LC-MS-MS) and liquid chromatography--quadrupole/time-of-flight mass spectrometry (LC-QTOF-MS). LC-MS-MS was also used for quantitative analyses, while LC-QTOF-MS for metabolite identification. Due to unusual matrices, the standard addition method was used for the quantitative determination of ADB-BUTINACA. The determined concentrations of ADB-BUTINACA in blood, lung, stomach, liver and kidney were 8.1 ng/mL, 6.4 ng/g, 1.5 ng/g, 1.8 ng/g and 0.4 ng/g, respectively. Apart from ADB-BUTINACA, the monohydroxylated metabolites and the dihydrodiol metabolite were detected and identified in all analyzed materials, and moreover the product of N-debutylation was found in blood and liver. The described case presents the identification and quantitation of a new synthetic cannabinoid ADB-BUTINACA in postmortem dog specimens. Although the cause of death was acute gastric dilatation, it cannot be ruled out that this process was the result of synthetic cannabinoid inhalation. Due to dogs' sensitivity to cannabinoids, ADB-BUTINACA poisoning cannot be excluded either. The described case suggests that ADB-BUTINACA elicits serious adverse effects in dogs. The article also indicates the dangers to which police dogs coming into contact with extremely potent drugs may be exposed.

Effects of a supplement containing Cannabidiol (CBD) on sedation and ataxia scores and health: Effects of Cannabidiol on Sedation and Ataxia

Supplements containing Cannabidiol (CBD) are available for horses, however, few studies have been published on their effects on behavior and health parameters. The purpose of this study was to determine if a daily oral supplement containing CBD would cause sedation, ataxia or alterations in other health parameters during administration for 56 days. Twenty clinically healthy adult Thoroughbred horses were housed in stalls. Before treatment was initiated, a complete physical examination, complete blood count (CBC) and biochemical panel were evaluated. In addition, horses were examined for sedation and ataxia using standard scoring systems. Horses were randomly divided into two treatment groups, treated (supplement pellets containing CBD as Hemp Extract, 150 mg) or control (supplement pellets without CBD). Horses were treated daily and sedation and ataxia scores were assigned by two masked observers once weekly for 56 days. Horses were monitored daily for clinical signs or adverse events and body weights were recorded weekly. A CBC and biochemical panel were repeated on days 28 and 56, two hours after administration of the supplement. The supplement was readily consumed by the horses and no adverse effects were seen over the treatment period. Sedation and ataxia scores ranged from 0 to 2 for all horses during the weekly examinations and there was no statistical difference between treatment groups. There were no treatment effects on blood values, including indicators of anemia and blood proteins, liver enzymes, kidney values, electrolytes or calcium. Body weight significantly increased in all horses, by Day 56 compared to Day 0 but no treatment by day effect was noted. The CBD supplement (150 mg) was readily consumed and safe and did not result in changes in mentation, gait, or other health parameters, and no adverse clinical signs were observed during 56 days of oral administration.

The Potential Proconvulsant Effects of Cannabis: a Scoping Review

INTRODUCTION

Cannabis' effect on seizure activity is an emerging topic that remains without consensus and merits further investigation. We therefore performed a scoping review to identify the available evidence and knowledge gaps within the existing literature on cannabis product exposures as a potential cause of seizures in humans.

METHODS

A scoping review was conducted in accordance with the PRISMA Extension for Scoping Reviews guidelines. The PubMed and Scopus databases were searched over a 20-year period from the date of the database query (12/21/2020). Inclusion criteria were (1) English language original research articles, (2) inclusion of human subjects, and (3) either investigation of seizures as a part of recreational cannabinoid use OR of exogenous cannabinoids as a cause of seizures.

RESULTS

A total of 3104 unique articles were screened, of which 68 underwent full-text review, and 13 met inclusion/exclusion criteria. Ten of 11 studies evaluating acute cannabis exposures reported a higher seizure incidence than would be expected based on the prevalence of epilepsy in the general and pediatric populations (range 0.7-1.2% and 0.3-0.5% respectively). The remaining two studies demonstrated increased seizure frequency and/or seizure-related hospitalization in recreational cannabis users and those with cannabis use disorder.

CONCLUSIONS

This scoping review demonstrates that a body of literature describing seizures in the setting of cannabis exposure exists, but it has several limitations. Ten identified studies showed a higher than expected incidence of seizures in populations exposed to cannabis products. Based on the Bradford Hill criteria, delta-9 tetrahydrocannabinol (THC) may be the causative xenobiotic for this phenomenon.

Single dose and chronic oral administration of cannabigerol and cannabigerolic acid-rich hemp extract in fed and fasted dogs: Physiological effect and pharmacokinetic evaluation

The use of cannabinoids in veterinary medicine has been increasing exponentially recently and there is little information regarding the pharmacokinetics of cannabinoids except for cannabidiol (CBD) and tetrahydrocannabinol (THC), with even more sparse information related to their native acid forms found in cannabis. Cannabigerol (CBG) is the precursor molecule to cannabinoid formation in the cannabis plant which may have medicinal properties as well, yet there are no publications related to CBG or the native cannabigerolic acid (CBGA) in companion animal species. The aim of this study was to investigate similar dosing of CBG and CBGA from hemp plants that have been used for cannabidiol pharmacokinetic studies. Administration in the fed and fasted state was performed to better understand absorption and retention of these unique hemp-derived cannabinoids in dogs. Results suggest that when providing a hemp-derived CBG/CBGA formulation in equal quantities, CBGA is absorbed approximately 40-fold better than CBG regardless of being given to fed or fasted dogs. After twice daily dosing for two weeks at 2 mg/kg in the fasted and then fed state, no differences in the mean serum CBG (5 ng/ml) or CBGA (250 ng/ml) serum concentrations were observed between states. Importantly, physical examination, complete blood counts, and serum chemistry evaluations over the two weeks suggest no adverse events during this short-term dosing trial.

Marijuana toxicosis in 2 donkeys

Marijuana toxicosis is typically seen by companion animal veterinarians. However, with increased marijuana availability, there is a greater potential for toxicosis in other species. Herein we describe a case of suspected marijuana toxicosis in a female and a male American Mammoth donkey, aged 8 y and 20 y, respectively, fed cannabis buds. Both cases were presented because of depression and lethargy. However, the jenny had ataxia, mild colic, tachycardia, tachypnea, and decreased tongue tone. Plasma samples from the jenny on presentation and 3 d following hospitalization were submitted to the Kansas State Veterinary Diagnostic Laboratory to be screened for cannabinoids using high-pressure liquid chromatography coupled with tandem mass spectroscopy (HPLC-MS/MS). A single serum sample from the jack was taken on presentation and submitted to the Animal Health Diagnostic Center at Cornell University for Δ⁹-tetrahydrocannabinol (THC) and cannabidiol analysis using HPLC-MS/MS. THC was detected in all samples. Clinical signs were noted 24-36 h after ingestion, which included mild-to-moderate neurologic deficits, mild colic, tachycardia, tachypnea, and decreased tongue tone. Both donkeys recovered uneventfully within 24 h of peak effects. Utilizing a cannabinoid screening assay in collaboration with a veterinary diagnostic laboratory may be useful when an equine practitioner suspects marijuana toxicosis in a patient.

Spatial, temporal, and space-time clusters associated with opioid and cannabis poisoning events in U.S. dogs (2005–2014)

While a substantial amount of research has focused on the abuse of opioids and cannabinoids in human populations, few studies have investigated accidental poisoning events in pet populations. The objective of this study was to identify whether poisoning events involving opioids and cannabinoids clustered in space, time, and space-time, and compare the locations of clusters between the two toxicants. Data were obtained concerning reports of dog poisoning events from the American Society for the Prevention of Cruelty to Animals’ (ASPCA) Animal Poisoning Control Center (APCC), from 2005–2014. The spatial scan statistic was used to identify clusters with a high proportion of these poisoning events. Our analyses show that opioid and cannabinoid poisoning events clustered in space, time, and space-time. The cluster patterns identified for each toxicant were distinct, but both shared some similarities with human use data. This study may help increase awareness to the public, public health, and veterinary communities about where and when dogs were most affected by opioid and cannabinoid poisonings. This study highlights the need to educate dog owners about safeguarding opioid and cannabinoid products from vulnerable populations.

Prevalence and characteristics of cannabis-induced toxicoses in pets: Results from a survey of veterinarians in North America

Cannabis legalization in North America has coincided with an increase in reports of cannabis-induced toxicosis in pets, but the magnitude of this problem, as well as outcomes of these incidents remain unknown. Therefore, we examined the frequency, diagnostic criteria, clinical signs, and prognoses of cannabis toxicoses in pets in North America. We conducted an online survey between January, 2021 and April, 2021 targeting veterinarians practicing in Canada and the United States (US). Out of the 251 study participants, 191 practiced in Canada. Cannabis toxicosis was most commonly reported in dogs (n = 226 veterinarians), and the number of toxicosis cases increased significantly in Canada (p<0.0001) and the US (p = 0.002) after October, 2018. Frequently reported clinical signs of cannabis toxicosis included: urinary incontinence (n = 195), disorientation (n = 182), ataxia (n = 178), lethargy (n = 150), hyperesthesia (n = 134), and bradycardia (n = 112). Edibles were most commonly suspected to be the cause of toxicosis (n = 116). The most common route of exposure was ingestion (n = 135), while the most cited reason was ingestion while unattended (n = 135). Cannabis toxicosis was mostly diagnosed using supportive clinical signs (n = 229), the most common treatment was outpatient monitoring (n = 182), and pets were most often treated as out-patients (n = 103). The legalization of cannabis use in Canada and the US is likely an important factor associated with the increased cannabis toxicosis cases in pets; however, the legal status may also increase reporting. The medicinal use of cannabis by pet-owners for pets may also contribute to a portion of the reported toxicoses. Most pets that experienced cannabis toxicosis recovered completely, suggesting that most cannabis toxicoses do not result in long-term ill effects. Even though some deaths (n = 16) were reported in association with cannabis toxicosis, the presence of confounders such as toxins, and underlying conditions cannot be ruled out, emphasizing the need for rigorous controlled laboratory studies to investigate this important issue.

Slovenian Pet Owners' Experience, Attitudes, and Predictors Regarding Cannabinoid Use in Dogs and Cats

The aim of this study was to assess the personal experience and attitudes of Slovenian pet owners regarding cannabinoid (CBD) use and to identify the predictors of the first use and reuse of CBDs in dogs and cats. We hypothesized that positive attitudes toward CBDs, postmodern health values, and personal experience would be significant predictors of CBD use in animals. An open online survey targeted randomly selected Slovenian dog and cat owners, regardless of their experience with cannabis products. The questionnaire consisted of six sections related to demographic data and personal experience with CBD use, information about the participant's animal, experience with CBD use in the participant's animal, reasons for not using CBDs in their animal, attitudes toward CBD use in dogs and cats, and postmodern health values. Descriptive statistics were performed to analyze demographics, personal experience with CBD use, and experience with CBD use in dogs and cats. Hierarchical multiple regression using the enter method was performed to analyze the important predictors of CBD use. A total of 408 completed questionnaires were included in the statistical analysis. A substantial proportion (38.5%) of owners had already used CBDs to treat their animal. Positive attitudes and previous personal experience were significant (p < 0.05) predictors of first use and reuse of CBDs in pets, while postmodern health values were not. In conclusion, the decision to use CBDs for medicinal purposes is based on acquired information and personal experience. Veterinarians should be informed and familiar with CBDs as a treatment option. However, further research is essential to establish the use of CBDs in veterinary medicine. Improved laws and regulations are also needed to ensure that only high-quality medications are prescribed to dogs and cats.

Drug-drug interaction between cannabidiol and phenobarbital in healthy dogs

OBJECTIVE

To assess drug-drug interactions between cannabidiol (CBD) and phenobarbital (PB) when simultaneously administered to healthy dogs.

ANIMALS

9 healthy, purpose bred Beagles.

PROCEDURES

A 3-phase prospective, randomized pharmacokinetic (PK) interaction study of CBD and PB was performed as follows: phase 1, CBD PK determination and evaluation of CBD tolerability by 3 single-dose CBD (5 mg/kg, 10 mg/kg, and 20 mg/kg) protocols followed by 2-week CBD dosing; phase 2, a single-dose, 3-way, crossover PK study of CBD (10 mg/kg), PB (4 mg/kg), or CBD (10 mg/kg) administration plus PB (4 mg/kg); and phase 3, evaluation of chronic PB (4 mg/kg, q 30 d) administration followed by single-dose CBD (10 mg/kg) PK study.

RESULTS

Although there were variations in CBD PK variables in dogs receiving CBD alone or in conjunction with PB, significance differences in CBD PK variables were not found. No significant difference was observed in PB PK variables of dogs receiving PB alone or with CBD. During chronic CBD administration, mild gastrointestinal signs were observed in 5 dogs. At daily CBD doses of 10 to 20 mg/kg/d, hypoxia was observed in 5 dogs and increased serum alkaline phosphatase (ALP) activities (range, 301 to 978 U/L) was observed in 4 dogs. A significant increase in ALP activity was observed with chronic administration of CBD during phase 1 between day 0 and day 14.

CONCLUSIONS AND CLINICAL RELEVANCE

No significant PK interactions were found between CBD and PB. Dose escalation of CBD or adjustment of PB in dogs is not recommended on the basis of findings of this study.

Safety and tolerability of escalating cannabinoid doses in healthy cats

OBJECTIVES

The aim of this study was to determine the safety and tolerability of escalating doses of orally delivered cannabis oils predominant in cannabidiol (CBD), tetrahydrocannabinol (THC), or both CBD and THC in healthy cats.

METHODS

In this placebo-controlled, blinded study, 20 healthy adult cats were randomized to one of five treatment groups (n = 4 per group): two placebo groups (sunflower oil [SF] or medium-chain triglyceride oil [MCT]), or three plant-derived cannabinoid oil groups (CBD in MCT, THC in MCT or CBD/THC [1.5:1] in SF). Up to 11 escalating doses of each formulation were delivered orally via syringe to fasted subjects, with at least 3 days separating doses. Safety and tolerability were determined from clinical observations, complete blood counts (CBCs) and clinical chemistry. Plasma cannabinoids (CBD, THC) and metabolites (7-COOH-CBD, 11-OH-THC) were assessed.

RESULTS

Titration to maximum doses of 30.5 mg/kg CBD (CBD oil), 41.5 mg/kg THC (THC oil) or 13.0:8.4 mg/kg CBD:THC (CBD/THC oil) was safely achieved in all subjects. All observed adverse events (AEs) were mild, transient and resolved without medical intervention. Gastrointestinal AEs were more common with formulations containing MCT. Constitutional (lethargy, hypothermia), neurologic (ataxia) and ocular (protrusion membrana nictitans) AEs were more common with oils containing THC (CBD/THC and THC oils). There were no clinically significant changes in CBC or clinical chemistry across treatment groups. Higher plasma levels of the cannabinoids and their metabolites following administration of the CBD/THC combination product are suggestive of a pharmacokinetic interaction.

CONCLUSIONS AND RELEVANCE

This is the first feline study to explore the safety and tolerability of CBD and THC, alone and in combination, in a controlled research setting. These findings will inform veterinarians of the safety profile of cannabinoids, particularly when considering the potential therapeutic use of CBD in cats or recognizing clinical signs associated with accidental exposure to THC-containing products.

Marijuana toxicosis in dogs in Melbourne, Australia, following suspected ingestion of human faeces: 15 cases (2011-2020)

This retrospective case series describes a novel and unexpected source for marijuana toxicosis in dogs; suspected ingestion of human faeces containing Δ⁹ -tetrahydrocannabinol (THC). Medical records from four, 24-h veterinary emergency hospitals in Melbourne, Australia, were reviewed and 15 dogs met the criteria for inclusion in this case series. Clinical signs of marijuana toxicosis included ataxia (n = 13), mydriasis (n = 6), hyperaesthesia (n = 5), urinary incontinence (n = 4) and stupor (n = 3). A urine drug screening test was performed for eight dogs and all were positive for THC. Confirmation of ingestion of human faeces was based on owner-witnessed ingestion (n = 7) or the presence of faecal material within vomit (n = 8). Sites of human faecal exposure were recorded to be a local park (n = 10), beach (n = 1), camp site (n = 1) and walking trail (n = 1). Time from exposure to development of clinical signs ranged between 3 and 6 h (n = 4). All dogs survived to discharge. Ingestion of human faeces containing THC may lead to marijuana toxicosis in dogs. Veterinary staff and owners should be attentive in regard to using appropriate hygiene measures when managing these dogs.

Current review of hemp-based medicines in dogs

Medical use of Cannabis (or hemp) began thousands of years ago. In the 20th century, mechanisms of action were demonstrated with the discovery of its active substances, the phytocannabinoids, and its pharmacological targets, the endocannabinoid system. This system is composed of receptors, endogenous substances, and enzymes, and it participates in the modulation of physiological mechanisms in several species, including dogs. Studies indicate that changes in this system may contribute to the genesis of some diseases. Therefore, the use of substances that act on its components may help in the treatment of these diseases. The main phytocannabinoids described are ^Δ9- tetrahydrocannabinol (THC) and cannabidiol (CBD). In humans, the benefits of using CBD in several diseases have been demonstrated. The popularization of this type of treatment has also reached veterinary medicine, which on one hand was related to an increase in adverse event records, but on the other also allowed reports of anecdotal evidences of its effectiveness and safety in animals. Clinical studies published so far indicate that the use of CBD in dogs can be safe at given doses and can contribute to osteoarthritis and idiopathic epilepsy treatments. Clinical and pre-clinical studies and case reports were reviewed in this report to identify the main characteristics of hemp-based therapies in dogs, including its pharmacokinetics, pharmacodynamics, safety, and efficacy in the treatment of diseases.

Development of [18F]LU14 for PET Imaging of Cannabinoid Receptor Type 2 in the Brain

Cannabinoid receptors type 2 (CB2R) represent an attractive therapeutic target for neurodegenerative diseases and cancer. Aiming at the development of a positron emission tomography (PET) radiotracer to monitor receptor density and/or occupancy during a CB2R-tailored therapy, we herein describe the radiosynthesis of cis-[¹⁸F]1-(4-fluorobutyl-N-((1s,4s)-4-methylcyclohexyl)-2-oxo-1,2-dihydro-1,8-naphthyridine-3-carboxamide ([¹⁸F]LU14) starting from the corresponding mesylate precursor. The first biological evaluation revealed that [¹⁸F]LU14 is a highly affine CB2R radioligand with >80% intact tracer in the brain at 30 min p.i. Its further evaluation by PET in a well-established rat model of CB2R overexpression demonstrated its ability to selectively image the CB2R in the brain and its potential as a tracer to further investigate disease-related changes in CB2R expression.

Detecting and quantifying marijuana metabolites in serum and urine of 19 dogs affected by marijuana toxicity

Veterinarians diagnose marijuana toxicity based on clinical signs and history, or in conjunction with an over-the-counter (OTC) human urine drug screen. With the legalization of recreational marijuana use becoming more prevalent in the United States, a more accurate test to aid in the diagnosis of canine marijuana toxicity is needed. We collected urine and serum samples from 19 dogs with confirmed or suspected marijuana toxicosis from multiple veterinary hospitals and analyzed them with a novel UPLC-MS/MS method. Calibrations from 0.1 to 100 ng/mL and QC materials were prepared. Samples were extracted, purified, and eluted with solid-phase extraction. Urine samples were tested with an OTC human urine drug screen. The limit of detection (LOD) and lower limit of quantification (LLOQ) ranges for marijuana metabolites in serum were 0.05-0.25 ng/mL and 0.1-0.5 ng/mL, respectively. In urine, the LOD and LLOQ ranges for the metabolites were 0.05-0.1 ng/mL and 0.1-0.5 ng/mL, respectively. In serum, median and range of metabolite concentrations (ng/mL) detected included: THC, 65.0 (0.14-160); 11-OH-Δ⁹-THC, 4.78 (1.15-17.8); 11-nor-9-carboxy-Δ⁹-THC, 2.18 (0.71-7.79); CBD, 0.28 (0.11-82.5); and THC-glucuronide, 2.05 (0.72-18.3). In the 19 urine samples, metabolite: creatinine (ng: mg) values detected included: THC, 0.22 (0.05-0.74); 11-OH-Δ⁹-THC, 0; 11-nor-9-carboxy-Δ⁹-THC, 1.32 (0.16-11.2); CBD, 0.19 (0.12-0.26); THC-COOH-glucuronide, 0.08 (0.04-0.11); and THC-glucuronide, 0.98 (0.25-10.7). Twenty of 21 urine samples tested negative for THC on the urine drug screen. All 19 serum samples contained quantifiable concentrations of THC using our novel UPLC-MS/MS method. Utilizing a UPLC-MS/MS method can be a useful aid in the diagnosis of marijuana toxicosis in dogs, whereas using an OTC human urine drug test is not a useful test for confirming marijuana exposure in dogs because of the low concentration of THC-COOH in urine.

Operational Canine

Operational K9s encompass a unique population of working dogs that serve as a force multiplier in various civilian law enforcement, force protection, search and rescue, and humanitarian operations. These elite canines do not volunteer to serve, yet they are some of the most faithful and dependable operators in the field. They undoubtedly perform an invaluable service in today's society and are owed a tremendous debt of gratitude for their selfless service, loyalty, and sacrifices. This article describes the unique characteristics and occupational hazards that pertain to the community of Operational K9s.

The impact of state cannabis legislation, county-level socioeconomic and dog-level characteristics on reported cannabis poisonings of companion dogs in the USA (2009-2014)

With current trends in cannabis legalization, large efforts are being made to understand the effects of less restricted legislation on human consumption, health, and abuse of these products. Little is known about the effects of cannabis legalization and increased cannabis use on vulnerable populations, such as dogs. The objective of this study was to examine the effects of different state-level cannabis legislation, county-level socioeconomic factors, and dog-level characteristics on dog cannabis poisoning reports to an animal poison control center (APCC). Data were obtained concerning reports of dog poisoning events, county characteristics, and state cannabis legislation from the American Society for the Prevention of Cruelty to Animals’ (ASPCA) APCC, the US Census Bureau, and various public policy-oriented and government websites, respectively. A multilevel logistic regression model with random intercepts for county and state was fitted to investigate the associations between the odds of a call to the APCC being related to a dog being poisoned by a cannabis product and the following types of variables: dog characteristics, county-level socioeconomic characteristics, and the type of state-level cannabis legislation. There were significantly higher odds of a call being related to cannabis in states with lower penalties for cannabis use and possession. The odds of these calls were higher in counties with higher income variability, higher percentage of urban population, and among smaller, male, and intact dogs. These calls increased throughout the study period (2009–2014). Reporting of cannabis poisonings were more likely to come from veterinarians than dog owners. Reported dog poisonings due to cannabis appear to be influenced by dog-level and community-level factors. This study may increase awareness to the public, public health, and veterinary communities of the effects of recreational drug use on dog populations. This study highlights the need to educate dog owners about safeguarding cannabis products from vulnerable populations.

Cannabis, Cannabidiol Oils and Tetrahydrocannabinol-What Do Veterinarians Need to Know?

As cannabis-derived products have become more available, veterinarians are seeing more cases of toxicosis. In addition, animal owners are having an increasing interest in using these products for their pets. This review looks at the situation in Europe and North America, the different types of cannabis and cannabis-derived products with historical examples of use in animals, and the cannabis industry. The existing regulatory framework for use in humans and animals as medicines and/or supplements was examined. Finally, a review of the clinical indications for which medicinal cannabis is authorised, a discussion of toxicosis, and recommendations and warnings around medical cannabis use are presented.

Motivations and expectations for using cannabis products to treat pain in humans and dogs: a mixed methods study

BACKGROUND

Social media and academic literature suggest that more people are using cannabis to treat their own or their dog's chronic pain. This study identifies the reasons people use cannabis products to treat their own pain or their dog's pain and explores whether these products have fulfilled their expectations.

METHODS

An anonymous, online survey was used to collect quantitative and qualitative self-report data on respondents' perceptions, motivations and expectations about their or their dog's chronic pain and cannabis use. The analyses are based on U.S. adults who reported using cannabis products to treat their own (N = 313) or their dog's (N = 204) chronic pain. Quantitative responses from the two groups were compared using Chi-Square tests and qualitative data were analyzed using a thematic analysis.

RESULTS

Human patients and dog owners reported similar motivations for using cannabis products to treat chronic pain, with the more popular reasons being that cannabis products are natural, are preferred over conventional medication, are believed to be the best treatment or good treatment option for pain. Similar proportions of human patients and dog owners reported that the use of cannabis products fulfilled their expectations (86% vs. 82% respectively, χ2 (1, 200) = .59, p = .32). The qualitative data revealed that their expectations were met by reducing pain, increasing relaxation, and improving sleep, coping, functionality and overall well being. Additionally, the qualitative data suggests that cannabis products offer a return to normalcy and a restored sense of self to human and dog patients.

CONCLUSIONS

The results suggest that people choose cannabis products because they are natural and a possible solution to managing chronic pain when conventional medicines have not been effective. Most people report that their expectations regarding pain management are fulfilled by these products. More accurate assessments are vital, however, for understanding both the objective biomedical and subjective socioemotional benefits of cannabis products for effective pain management for human and dog patients. In addition, objective factual information regarding cannabis products for effective pain management in humans and dogs is needed. It is recommended that both physicians and veterinarians work towards feeling more comfortable proactively broaching the subject of cannabis use with additional training and education.

Probable cutaneous adverse drug reaction due to a cannabidiol-containing hemp oil product in a dog

BACKGROUND

Cannabidiol (CBD) in hemp oil has become a widely used product in veterinary medicine. To date, there have been no reports of cutaneous adverse events associated with CBD-containing oil in the veterinary literature.

CLINICAL SUMMARY

A 4-year-old castrated male Labrador retriever presented with pad sloughing and rapidly progressive cutaneous and mucosal ulceration within five days of administering an oral CBD oil product. Histopathological findings in combination with cutaneous signs were consistent with Stevens-Johnson syndrome. All lesions completely resolved after discontinuation of the hemp oil in addition to a 12 day course of cephalexin and prednisone. Given the lack of alternative causes including other medications, an adverse drug event was deemed probable according to the Naranjo algorithm.

CONCLUSIONS AND CLINICAL IMPORTANCE

To the best of the authors' knowledge, this is the first report of suspected cutaneous adverse drug reaction to a CBD-containing hemp oil product.

Pharmacokinetic and Safety Evaluation of Various Oral Doses of a Novel 1:20 THC:CBD Cannabis Herbal Extract in Dogs

Objective: To determine the pharmacokinetics (PK) and safety of various oral doses of a Cannabis herbal extract (CHE) containing a 1:20 ratio of Δ9-tetrahydrocannabinol (THC):cannabidiol (CBD) in 13 healthy Beagle-cross dogs.

Methods: Single-dose PK was assessed after oral administration of CHE at low, medium, or high doses [2, 5, or 10 mg CBD and 0.1, 0.25, or 0.5 mg THC per kg of body weight (bw), respectively; n = 6 per group]. Dogs were monitored for adverse events for up to 48 h post-dose. Evaluations of neurological signs, clinical laboratory abnormalities, and other adverse events were performed in two separate study phases: a multiple-dose phase with 12 dogs receiving five medium doses (5 mg CBD/kg bw) at 12 h intervals, and a single low-dose (2 mg CBD/kg bw), randomized, blinded, negative controlled study with 13 dogs.

Results: Cannabinoids CBD, THC, CBC, and metabolites 6-OH-CBD, 7-OH-CBD, 11-OH-THC, and THC-COOH were quantified in plasma. CBD and THC were rapidly absorbed (mean T_max of 1.9–2.3 h) and initially depleted rapidly (mean CBD T_1/2β of 2.3–2.6 h). A prolonged elimination phase (mean CBD T_1/2λ of 13.3–24.4 h) was observed. CBD and THC concentrations increased in a dose-dependent (non-linear) manner, with disproportionally greater cannabinoid exposure relative to the dose increase. Neurological signs (hyperesthesia or proprioceptive deficits) were noted in five of six dogs in the high-dose group, but only occasionally or rarely in the medium- and low-dose groups, respectively. Presence and severity of clinical signs correlated with plasma cannabinoid concentrations. Dogs appeared to develop a tolerance to cannabinoid effects after multiple CHE doses, with fewer neurological signs noted after the final (fifth) vs. first dose. No clinically meaningful changes in blood count or chemistry values occurred after multiple CHE doses.

Clinical Significance: Dogs tolerated the 1:20 THC:CBD formulation well at low and medium doses, but clinically meaningful neurological signs were observed at high doses. Because of non-proportional increases in plasma cannabinoid concentrations with increasing doses, as well as potential differences in CHE product composition and bioavailability, the possibility of adverse events and dose regimen consistency should be discussed with dog owners.

Unconventional diets and nutritional supplements are more common in dogs with cancer compared to healthy dogs: An online global survey of 345 dog owners

This survey aimed to investigate and compare diet type and supplement use between dogs (Canis lupus familiaris, L.) with cancer and a population of owner-reported healthy dogs and to assess the sources of information dog owners consult. Respondents were mainly from English-speaking countries. Dogs were considered healthy (N = 213) if owners reported them to be in good health. Dogs were included in the cancer group (N = 132) if the owner reported that their dog had been diagnosed with cancer. An online survey was distributed to clients presenting to a tertiary oncology service, clients presenting to a local primary care veterinary practice, and through social media. Owners of dogs with cancer spent more time researching pet health (P < .001), pet nutrition (P < .01) and nutritional supplements (P < .001) than owners of healthy dogs. While veterinarians were most commonly reported to be an information source for both groups, owners of healthy dogs more likely consulted pet stores and owners of dogs with cancer tended more to social media groups and blogs. Healthy dogs were more likely fed commercial dry food (P < .001), whereas homemade cooked (P < .001) and raw diets (P < .05) were more prevalent among dogs with cancer. Supplement use, especially cannabidiol products, mushroom extracts or turmeric/curcumin, was also more common for this group (P < .001). Alternative diets and supplements were more popular among owners of dogs with cancer compared to owners of healthy dogs. These findings highlight the need for nutritional counselling and education of pet owners regarding nutrition-related topics, especially when their dog is diagnosed with cancer.

Cannabis, One Health, and Veterinary Medicine: Cannabinoids' Role in Public Health, Food Safety, and Translational Medicine

Public health is connected to cannabis with regard to food, animal feed (feed), and pharmaceuticals. Therefore, the use of phytocannabinoids should be examined from a One Health perspective. Current knowledge on medical cannabis treatment (MCT) does not address sufficiently diseases which are of epidemiological and of zoonotic concern. The use of cannabinoids in veterinary medicine is illegal in most countries, mostly due to lack of evidence-based medicine. To answer the growing need of scientific evidence-based applicable medicine in both human and veterinary medicine, a new approach for the investigation of the therapeutic potential of cannabinoids must be adopted. A model that offers direct study of a specific disease in human and veterinary patients may facilitate development of novel therapies. Therefore, we urge the regulatory authorities-the ministries of health and agriculture (in Israel and worldwide)-to publish guidelines for veterinary use due to its importance to public health, as well as to promote One Health-related preclinical translational medicine studies for the general public health.

Single-Dose Pharmacokinetics and Preliminary Safety Assessment with Use of CBD-Rich Hemp Nutraceutical in Healthy Dogs and Cats

The use of CBD-rich hemp products is becoming popular among pet owners with no long-term safety data related to consumption in adult dogs and cats. The purpose of this study was to determine the single-dose oral pharmacokinetics of CBD, and to provide a preliminary assessment of safety and adverse effects during 12-week administration using a hemp-based product in healthy dogs and cats. Eight of each species were provided a 2 mg/kg total CBD concentration orally twice daily for 12 weeks with screening of single-dose pharmacokinetics in six of each species. Pharmacokinetics revealed a mean maximum concentration (Cmax) of 301 ng/mL and 43 ng/mL, area under the curve (AUC) of 1297 ng-h/mL and 164 ng-h/mL, and time to maximal concentration (Tmax) of 1.4 h and 2 h, for dogs and cats, respectively. Serum chemistry and CBC results showed no clinically significant alterations, however one cat showed a persistent rise in alanine aminotransferase (ALT) above the reference range for the duration of the trial. In healthy dogs and cats, an oral CBD-rich hemp supplement administered every 12 h was not detrimental based on CBC or biochemistry values. Cats do appear to absorb or eliminate CBD differently than dogs, showing lower serum concentrations and adverse effects of excessive licking and head-shaking during oil administration.

The Endocannabinoid System of Animals

Simple Summary

Our understanding of the Endocannabinoid System of animals, and its ubiquitous presence in nearly all members of Animalia, has opened the door to novel approaches targeting pain management, cancer therapeutics, modulation of neurologic disorders, stress reduction, anxiety management, and inflammatory diseases. Both endogenous and exogenous endocannabinoid-related molecules are able to function as direct ligands or, otherwise, influence the EndoCannabinoid System (ECS). This review article introduces the reader to the ECS in animals, and documents its potential as a source for emerging therapeutics.

Abstract

The endocannabinoid system has been found to be pervasive in mammalian species. It has also been described in invertebrate species as primitive as the Hydra. Insects, apparently, are devoid of this, otherwise, ubiquitous system that provides homeostatic balance to the nervous and immune systems, as well as many other organ systems. The endocannabinoid system (ECS) has been defined to consist of three parts, which include (1) endogenous ligands, (2) G-protein coupled receptors (GPCRs), and (3) enzymes to degrade and recycle the ligands. Two endogenous molecules have been identified as ligands in the ECS to date. The endocannabinoids are anandamide (arachidonoyl ethanolamide) and 2-AG (2-arachidonoyl glycerol). Two G-coupled protein receptors (GPCR) have been described as part of this system, with other putative GPC being considered. Coincidentally, the phytochemicals produced in large quantities by the Cannabis sativa L plant, and in lesser amounts by other plants, can interact with this system as ligands. These plant-based cannabinoids are termed phytocannabinoids. The precise determination of the distribution of cannabinoid receptors in animal species is an ongoing project, with the canine cannabinoid receptor distribution currently receiving the most interest in non-human animals.

A survey of veterinary student attitudes concerning whether marijuana could have therapeutic value for animals

Marijuana is increasingly recognized for its therapeutic value in human medicine. Although most veterinary research to date has been concerned with marijuana toxicity, there is some interest in the potential therapeutic value of marijuana in veterinary medicine. With the recent legalization of marijuana for recreational use in Canada in October 2018, there is a need for veterinarians and veterinary students to be in a position to address client questions and concerns on this topic. We distributed a questionnaire to current veterinary students at the Ontario Veterinary College in Guelph, Ontario, to determine their attitude(s) towards marijuana as a potential therapeutic agent in animals. The overall response rate for the questionnaire was 43.5% (207/476). Most students felt that marijuana has potential therapeutic value in animals (53.6%; 111/207), fewer were unsure (38.6%; 80/207), and a small number of students felt that marijuana does not have potential therapeutic value in animals (7.7%; 16/207). Data generated by this questionnaire identified an important distinction between two major active compounds found in marijuana: cannabidiol (CBD) and tetrahydrocannabinol (THC). Potential barriers to use in veterinary practice were also identified, including stigma and toxicity. Finally, many respondents showed an awareness of the limited scientific research regarding the safety and efficacy of marijuana in animals. Until a body of scientific literature on marijuana in animals becomes available, veterinarians may benefit from having an awareness of the different physiological and pharmacokinetic effects produced by different strains (including any adverse effects, and half-life), and a general understanding of current therapeutic applications of marijuana in humans.

Anorexia and the Cancer Patient

Appetite influences perceived quality of life for a dog or cat with cancer. Inappetence often is multifactorial, complicating treatment. Cancer-related anorexia/cachexia syndrome is a metabolic, paraneoplastic syndrome characterized by decreased food intake, involuntary weight loss, and loss of fat and muscle. If weight loss/cachexia has an impact on canine and feline cancer patients as in humans, management may improve survival times and quality of life. The challenge is having effective, proved therapies available for clinical use. Recent Food and Drug Administration approvals for appetite stimulation have renewed interest and discussion and has the potential to alter the course of case management.