As cannabis becomes more widely used for human medical purposes in the United States, many pet owners are interested in its potential to treat their pets’ anxiety, chronic pain, seizures, and other conditions. Any veterinary professional who has spent time with clients in recent years has likely been asked at some point about using cannabidiol (CBD), which is now found in a variety of supplements marketed for animal use.

Even if the veterinarian has reservations about recommending these products due to legal concerns and limited scientific evidence confirming their safety and efficacy in animals, pet owners are finding and administering cannabinoid products on their own, which makes it a necessary topic for every veterinary team to at least know the basics about.

What is cannabis?

According to the Veterinary Cannabinoid Academy, “cannabis” can be used to describe any plant of the genus Cannabis sativa L., which includes plants commonly called hemp, ruderalis, and marijuana.

All cannabis plants contain cannabinoids, defined as a substance that interacts with the cannabinoid receptors in the body. The most well-known and studied of the more than 113 identified cannabinoids are tetrahydrocannabinol (THC), the component that is principally responsible for producing a high in those who consume it, and cannabidiol (CBD).

CBD does not have an intoxicating effect and is typically obtained from hemp plants, defined as having less than 0.3% THC concentration by dry weight. The federal government de-scheduled hemp plants in 2018, meaning they are not considered to be controlled substances.

Latest cannabis studies

A new study performed by the Waltham Petcare Science Institute in the United Kingdom, and funded by Mars PetCare, aimed to demonstrate the safety of long-term use of CBD in healthy dogs. In this randomized, placebo-controlled, blinded study, investigators administered a pure distillate of CBD at a dose of 4 mg/kg daily by mouth in a capsule to 40 healthy, well-cared for dogs in a research colony for 6 months.

The researchers demonstrated that no adverse clinical signs were noted in any of the dogs, and that no significant blood chemistry abnormalities were detected apart from a transient alkaline phosphatase (ALP) elevation in about half of the dogs.

This elevation was determined to not be of any clinical significance in terms of liver function or liver injury, since all other values related to liver health remained within normal limits, and a large increase in the bone-specific isoform of ALP (BALP) was detected.

The BALP elevation was thought to be a sign of increased osteoblast activity, and no significant increase in osteoclast activity was measured. This suggested to the researchers that the CBD may support bone growth in dogs as has been demonstrated previously in other species.

When and how CBD works best

Stephen Cital, RVT, SRA, RLAT, CVPP, VTS-LAM, Co-Founder of the Veterinary Cannabinoid Academy and chief editor of the textbook Cannabis Therapy in Veterinary Medicine, is pleased to see another veterinary study highlighting the safe long-term use of CBD in dogs. He points out that it is not the first such study, but that hopefully it will help more veterinary practitioners feel comfortable considering CBD as part of their patients’ treatment plan when their clients are interested in it.

As a certified veterinary pain practitioner and a participant in previous research studies involving CBD use in animals , he has seen “good success with using them to aid in patient comfort, decrease in seizure activity, skin issues, and GI issues.”

Surprisingly, he has noted less success in treating stress and anxiety, the conditions for which it is probably sought the most, other than pain. He notes that while some sedation may be achieved, this should not be mistaken for true anxiolytic effects.

He believes that more efficacy studies involving the use of CBD and other cannabinoids in animals will help to better define how different cannabinoids work together and in combination for various indications in animals.

But is CBD legal? And other things to watch for …

For veterinary professionals who are concerned about legally recommending products containing CBD or other cannabinoids, Cital recommends researching your state laws regarding hemp-derived products.

He also recommends that when evaluating the quality and purity of a particular product, it’s best to request a Certification of Analysis (COA) from the manufacturer for the specific batch of product to be used. If the manufacturer is not willing to provide it, or if the information provided on it does not match with the claims on the product packaging, a different product should be chosen.

If an animal is expected to take a cannabinoid product for more than 3 months, a blood chemistry should be performed prior to starting the supplement and repeated every 3–6 months. Additionally, CBD should be discontinued in animals underdoing elective surgical procedures at least 3 days prior to the procedure due to a concern about prolonged blood clotting times with CBD.

Cital cautions that veterinarians should not recommend or sell any type of product that does contain more than 0.3% THC, as those are still considered to be schedule I drugs. Furthermore, any state laws that decriminalize use and prescription of such products in humans do not apply to use in animals.

Veterinarians should also not sell a CBD product that makes claims on its label that it treats or cures any disease or condition. The sale of these products by a veterinarian could constitute the illegal sale of a non-FDA approved drug. If a client asks about a product that makes these types of claims, veterinarians can provide harm reduction education and document it in the patient’s medical record.

The future of CBD

Clearly CBD will continue to be an area of high interest in veterinary medicine going forward. Cital hopes that veterinary professionals will continue to become more comfortable considering cannabinoids in general as an option for pets whose owners want to use them. He is particularly excited about the potential antineoplastic effects of cannabinoids and terpenes (“essential oils” found in hemp plants that are synergistic with and supportive of cannabinoids), an area that is currently being studied.

The AVMA is also encouraging continued clinical research on the use of cannabinoids in animals, in hopes that eventually an FDA-approved drug will be available for use in veterinary medicine. In the meantime, we can continue to counsel our clients about what is known and what is unknown, assist them in making the most informed decision possible, and hopefully feel a little more empowered and comfortable doing so.

Further reading

Cannabidiol (CBD): What we know and what we don’t
https://www.health.harvard.edu/blog/cannabidiol-cbd-what-we-know-and-what-we-dont-2018082414476

The Veterinary Cannabinoid Academy
https://www.vetcannacademy.com/

Cannabis use and pets
https://www.avma.org/resources-tools/animal-health-and-welfare/cannabis-use-and-pets

Emily Singler, VMD, is a 2001 graduate of Penn State University and a 2005 graduate of University of Pennsylvania School of Veterinary Medicine. She has worked in shelter medicine, private practice, and as a relief veterinarian. She currently works as a veterinary writer and consultant and has her own blog, www.vetmedbaby.com. Emily also writes a monthly column for NEWStat exploring One Health and the human-animal bond.