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Not to Stir the Pot But...

Pot. Weed. Marijuana. THC. CBD. Cannabis sativa plants and their various components are called many things. Cannabis has a long history of use by people as an herbal medicine, dating back thousands of years. However, for various political and societal reasons, cannabis was vilified in the early 1900s and later classified as a Schedule I drug in 1972.

Cannabidiol, or CBD, is one of the over 100 cannabinoids found in cannabis, and is not mind-altering. It acts on different parts of the nervous system than Tetrahydrocannabinol, or THC, which is the well-known psychoactive cannabinoid in marijuana. In recent years the use of CBD supplements in humans has taken off, believed to help with conditions such as chronic pain and anxiety. Not surprisingly, the use of CBD supplements is on the rise in animals as well.

CBD supplements can be derived from either marijuana or hemp. Hemp contains very low concentrations (0.3% or less) of THC whereas marijuana contains much higher concentrations, up to 40%. Due to the low levels of THC, hemp, which is primarily used for industrial purposes, was removed as a Schedule I substance and reclassified as an agricultural commodity under the Agricultural Improvement Act of 2018.

We’ve been asked if we recommend using CBD in horses for various conditions but at this time we cannot recommend its use in horses, or in any animals. Here’s why…

  • There are a plethora of legal grey areas.

  • Marijuana-Derived CBD is still federally illegal and on a state-level it’s not legal for use in animals.

  • Federal law prohibits the use of cannabis for medicinal or recreational purposes. While over half the states, including Washington, have legalized it for medical use in humans, it is still illegal for use in animals on a state level.

  • The US Drug Enforcement Administration (DEA), who has the power to reclassify cannabis to a Schedule 2 drug under the Controlled Substances Act, denied a petition to do so based on the recommendations of the US Department of Health and Human Services (HHS) in 2016.

  • Of major note is that the US Food and Drug Administration (FDA), who approves and regulates products with therapeutic claims, has approved only one product derived from cannabis for use in people who suffer from seizures related to two rare forms of epilepsy. Otherwise, they have not approved the use of the cannabis as medicine in any other form or product

  • The 2018 bill did not legalize CBD regardless of what it's derived from.

  • CBD from hemp must adhere to certain regulations in order to be removed as a Schedule I substance and be legal.

  • These regulations include containing less than 0.3% THC, adhering to shared state-federal regulations, and being grown by a properly licensed grower.

  • There is a lack of scientific data on the use of CBD in horses.

  • While there are some studies supporting the use of CBD for therapeutics in humans, there are very limited amounts of scientific evidence for its use in animals. Most of the claims regarding the benefits of the use of CBD in animals are based on anecdotal evidence or extrapolated from studies performed on rodents.

  • There is no published data on the metabolism or withdrawal times of CBD in horses. This means if you use a product, it is possible it could show up on a drug test if you are competing at a regulated show. (FEI and USEF both ban natural & synthetic Cannabinoids and other cannabimimetics.)

  • CBD can interact with other medications, and we don’t know how it reacts to drugs commonly used in horses.

  • Dosage recommendations on supplements aren’t necessarily based on anything other than a best guess as to what would be effective by the people making the product.

  • CBD oils and supplements aren’t regulated.

  • Since the FDA hasn’t approved cannabis for use as medicine (other than the one product), CBD products aren’t regulated, aren’t produced under the guidance of good manufacturing practices, and aren’t subject to federal regulations regarding labeling, purity and reliability. Meaning there are no assurances as to their efficacy, safety, content, purity, bioavailability, and consistency between batches.

  • Some oils aren’t pure and can contain trace amounts of THC, which is toxic in some animals, and other substances.

  • While we may recommend unregulated supplements for things like joint health, they do not potentially contain a Schedule I drug like hemp-derived CBD supplements can.

A lot more research needs to be done to determine whether CBD is beneficial in horses. The trick with this is that as long as marijuana is federally listed as a Schedule I drug, the ability of scientists and researchers to study the use of cannabis for new therapeutics or drugs is much more challenging. With the recent reclassification of hemp, hemp-derived CBD studies are becoming more widespread, including in veterinary medicine, and we look forward to seeing what the results of these studies show.

As veterinarians we can’t risk recommending something that could affect our ability to practice and that doesn’t have enough research behind it to support its therapeutic usage. We don’t know what route of administration is most effective, what dosage will result in desired benefits, or if there are any long-term risks with chronic use of CBD. We are always open to new drugs and therapies for horses, and if down the road the legalities surrounding Cannabis become less of a tangled web, and there is research and data to support it's use in horses, we will consider it's utility on a case-by-case basis.

History. "Marijuana.", Accessed 19 April 2019.

National Center for Biotechnology Information. "The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research.", Accessed 19 April 2019.

Centers for Disease Control and Prevention. "Marijuana and Public Health." Accessed 19 April 2019.

American Veterinary Medical Association. "Cannabis Use and Pets.", Accessed 19 April 2019.

Veterinary Information Network News Service. "Veterinarians implore AVMA to address marijuana in animals.", Accessed 19 April 2019.

National Center for Biotechnology Information. "An Update on Safety and Side Effects of Cannabidiol: A Review of Clinical Data and Relevant Animal Studies.", Accessed 19 April 2019.

Fédération Equestre Internationale. "2019 Equine Prohibited Substances List.", Accessed 19 April 2019.

Image by Lindsay66 from Pixabay Image by OpenClipart-Vectors from Pixabay

Title courtesy of Dr. Lauren Watson

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