Cannabidiol and the possibilities of its use in veterinary medicine of dogs and horses: A brief review

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.

Improved quality of life and pain relief in mature horses with osteoarthritis after oral transmucosal cannabidiol oil administration as part of an analgesic regimen

The aim of this study was to evaluate the effect of oral cannabidiol (CBD) administration in addition to a conventional analgesic protocol on the clinical signs of 20 horses with mild joint osteoarthritis. The horses were randomly assigned to either the control group (C group) or the cannabidiol group (CBD group). Both groups were treated with phenylbutazone for 5 days. The CBD group received 0.03 mg/kg cannabidiol in hemp oil orally once daily for 14 days in addition to phenylbutazone treatment. All subjects were monitored for clinical parameters, oxidative status and blood counts. Pain and quality of life were also assessed using the Horse Chronic Pain Scale (HCPS). The CBD group showed a significant reduction in heart rate, respiratory rate, white blood cell count and oxidative stress (malondialdehyde lipid peroxidation). A significant reduction in HCPS scores was seen in both groups. Lower scores were recorded in the CBD group (3 med; range: 2/4) than in the C group (7 med; range: 4/10). The addition of a cannabidiol-based product to an analgesic protocol was well tolerated and showed positive effects on the treated subjects, improving their quality of life and pain relief.

Cannabis and pathologies in dogs and cats: first survey of phytocannabinoid use in veterinary medicine in Argentina

BACKGROUND

In animals, the endocannabinoid system regulates multiple physiological functions. Like humans, animals respond to preparations containing phytocannabinoids for treating several conditions. In Argentina, laws 27350 and 27669 have expanded the possibility of studying beneficial and adverse effects.

MATERIALS AND METHODS

We conducted a web-based survey of Argentinian Cannabis Veterinarians to make a situational diagnosis on the number of veterinary medicine professionals currently developing treatments with cannabinoids focusing on dogs and cats.  RESULTS: Among the species treated, 77% corresponded to dogs, while 21% were cats. Pain, seizures, and behavior disorders are the most prevalent conditions in dogs. Seven conditions and combinations were treated in cats. Full-spectrum cannabis extract derived from three different chemotypes was administered alone or with standard medication. Response to cannabis treatment was characterized based on improvement categorized according to clinical assessment. Both dogs and cats showed different improvement grades in clinical signs.

CONCLUSION

This analysis provides promising results regarding the medicinal use of cannabis in dogs and cats. Based on this analysis, we propose to expand the training of professionals, obtain quality preparations, and initiate controlled trials to reinforce knowledge of the use of cannabinoids in veterinary medicine.

Hepatic biotransformation of non-psychotropic phytocannabinoids and activity screening on cytochromes P450 and UDP-glucuronosyltransferases

This study examined the biotransformation of phytocannabinoids in human hepatocytes. The susceptibility of the tested compounds to transformations in hepatocytes exhibited the following hierarchy: cannabinol (CBN) > cannabigerol (CBG) > cannabichromene (CBC) > cannabidiol (CBD). Biotransformation included hydroxylation, oxidation to a carboxylic acid, dehydrogenation, hydrogenation, dehydration, loss/shortening of alkyl, glucuronidation and sulfation. CBN was primarily metabolized by oxidation of a methyl to a carboxylic acid group, while CBD, CBG and CBC were preferentially metabolized by direct glucuronidation. The study also screened for the activity of recombinant human cytochromes P450 (CYPs) and UDP-glucuronosyltransferases (UGTs), which could catalyze the hydroxylation and glucuronidation of the tested compounds, respectively. We found that CBD was hydroxylated mainly by CYPs 2C8, 2C19, 2D6; CBN by 1A2, 2C9, 2C19 and 2D6; and CBG by 2B6, 2C9, 2C19 and 2D6. CBC exhibited higher susceptibility to CYP-mediated transformation than the other tested compounds, mainly with CYPs 1A2, 2B6, 2C8, 2C19, 2D6 and 3A4 being involved. Further, CBD was primarily glucuronidated by UGTs 1A3, 1A7, 1A8, 1A9 and 2B7; CBN by 1A7, 1A8, 1A9 and 2B7; CBG by 1A3, 1A7, 1A8, 1A9, 2B4, 2B7 and 2B17; and the glucuronidation of CBC was catalyzed by UGTs 1A1, 1A8, 1A9 and 2B7.

Pharmacokinetic modelling of orally administered cannabidiol and implications for medication control in horses

Cannabidiol (CBD) products gain increasing popularity amongst animal owners and veterinarians as an alternative remedy for treatment of stress, inflammation or pain in horses. Whilst the use of cannabinoids is banned in equine sports, there is limited information available concerning CBD detection times in blood or urine. The aim of this study was to determine the pharmacokinetic properties of CBD following oral administration in the horse to assist doping control laboratories with interpreting CBD analytical results. Part 1: dose escalation study: Single oral administration of three escalating doses of CBD paste (0.2 mg/kg, n = 3 horses; 1 mg/kg, n = 3; 3 mg/kg, n = 5) with >7 days wash-out periods in between. Part 2: multiple dose study: oral administration of CBD paste (3 mg/kg, n = 6) twice daily for 15 days. Multiple blood and urine samples were collected daily throughout both studies. Following study part 2, blood and urine samples were collected for 2 weeks to observe the elimination phase. Concentrations of CBD, its metabolites and further cannabinoids were evaluated using gas-chromatography/tandem-mass-spectrometry. Pharmacokinetic parameters were assessed via two approaches: population pharmacokinetic analysis using a nonlinear mixed-effects model and non-compartmental analysis. AUC0-12 h and Cmax were tested for dose proportionality. During the elimination phase, the CBD steady-state urine to serum concentration ratio (Rss) was calculated. Oral CBD medication was well-tolerated in horses. Based on population pharmacokinetics, a three-compartment model with zero-order absorption most accurately described the pharmacokinetic properties of CBD. High volumes of distribution into peripheral compartments and high concentrations of 7-carboxy-CBD were observed in serum. Non-compartmental analysis identified a Cmax of 12.17 ± 2.08 ng/mL after single administration of CBD (dose: 3 mg/kg). AUC0-12 h showed dose proportionality, increase for Cmax leveled off at higher doses. Following multiple doses, the CBD terminal half-life was 161.29 ± 43.65 h in serum. Rss was 4.45 ± 1.04. CBD is extensively metabolized and shows high volumes of tissue distribution with a resulting extended elimination phase. Further investigation of the potential calming and anti-inflammatory effects of CBD are required to determine cut-off values for medication control using the calculated Rss.