What veterinarians need to know
Marijuana is federally designated as a schedule I controlled substance in the United States under the Controlled Substances Act – with the exception of "hemp" (Cannabis sativa L with tetrahydrocannabinol <0.3% dry weight), a type of cannabis that was recently descheduled through passage of the 2018 Farm Bill. How marijuana is handled under federal law contrasts with how it is handled under state law. More than half of U.S. states have passed legislation permitting medicinal use of marijuana in humans under strict guidelines. Additional states have passed laws permitting its recreational use. State laws legalizing use in people do not apply to cannabis use in animals.
As cannabis-derived products have become more available, veterinarians have seen increased interest among clients in using these products for their pets. These clients understandably are asking, "Are these products legal, safe, and effective for treating medical conditions in animals?" Our FAQs on the regulatory status of cannabis, cannabis-derived, and cannabis-related products can help you understand the legal landscape.
For a detailed guide to cannabis and its impact on veterinary medicine, view Cannabis in veterinary medicine.
Safety and efficacy
Under the federal Food, Drug, and Cosmetic Act, products for which therapeutic claims are made must be approved by the FDA in order to be legally manufactured and marketed. The FDA approval process is the means by which the safety and efficacy of such products is demonstrated. Assurance regarding the efficacy and safety of products is obviously important to veterinarians who are considering whether to use them in the treatment of their patients.
Cannabis-derived products that have been suggested as therapeutic agents for use in animals to-date have not followed the traditional path to FDA approval. Relatedly, although cannabinoids such as CBD appear to hold therapeutic promise in areas such as the treatment of epilepsy and the management of pain and inflammation associated with osteoarthritis, the available scientific evidence pertaining to their use in animals is currently limited. While findings from a few well-controlled studies have been published, much of what we know is related to anecdotal or case reports or has been gleaned from studies related to use in humans, including the study of animal models for that purpose. The AVMA continues to encourage well-controlled clinical research and pursuit of FDA approval by manufacturers of cannabis-derived products so that high-quality products of known safety and efficacy can be made available for veterinarians and their patients.
Also of concern are recent reports of lab analyses indicating that a substantial portion of products currently available on the market are labelled inaccurately with respect to both the identity and amount of active ingredient found within the product.
In July 2019, the AVMA submitted comments to the FDA urging the agency to provide regulatory clarity about expectations for the labeling, safety, and use of cannabis-derived and cannabis-related products. This is critical to assure the safe and appropriate use of these products in animal drugs, food, feed, and food/feed additives. You can read our full comments here.
A single product derived from cannabis has been approved by the FDA for use in people who suffer from seizures related to particular syndromes. That drug can be used in an extralabel manner by veterinarians in accord with the Animal Medicinal Drug Use Clarification Act (AMDUCA).
Veterinary cases of cannabis toxicosis in dogs stem most commonly from exposure to edibles. In these cases, there may be additional toxic ingredients involved – such as chocolate, raisins, or xylitol – which result in a poorer prognosis. Cats may also directly consume the plant material.
There are a wide range of clinical signs that have been associated with cannabis toxicosis. A classic presentation is a depressed or ataxic dog that is dribbling urine. Several deaths have been reported due to cannabis toxicity, and these appear to be the result of associated complications, such as aspiration. If you know or suspect your pet of having been exposed to any form of cannabis please consult your veterinarian immediately.
Federal and state laws regarding cannabis products are complex, and the legal landscape around these products is evolving. We've summarized the regulatory landscape surrounding use of these products in Cannabis as drug, food or supplement in veterinary medicine, and also provided an update incorporating additional information published by federal agencies.