The approval of cannabis among people has captivated pet owners’ curiosity about how the drug might help cats and dogs suffering from pain, anxiety, and other ills. Veterinarians wanting to help, though, often face unclear rules, which discourages them from even talking about cannabis, prompting many clients to medicate their animals without professional guidance. Now, rising shifts in the US legal system may give veterinarians more leeway to not only discuss the alleged pros, cons, and unknowns of cannabis use with clients but to recommend, prescribe and administer it, too.
In a noteworthy development, the US Department of Health and Human Services in August 2023 recommended easing federal restrictions on cannabis. Moreover, four states — California, Michigan, Nevada and Utah — have implemented laws explicitly for its use in veterinary medicine. California, for example, last year started letting veterinarians recommend cannabis therapeutically for animal patients. Before this legislation, pet owners had no one to turn to except budtenders and pet shop owners.
However, despite legislative and regulatory action at the state and federal levels, the actual authority controlling legal access to cannabis as medicine is the US Food and Drug Administration. For veterinarians, this means there is no legal way to use or recommend non-FDA-approved drugs because the Extralabel Drug Rules require veterinarians to reach for the FDA-approved drug first. Furthermore, since there are FDA-approved human drugs containing cannabis, veterinarians are expected to start there.
When veterinarians call cannabis a treatment, they usually talk about cannabidiol (CBD), a non-intoxicating chemical produced by the plant. Some of the uncertainty about cannabis owes to concern that another chemical the plant produces, tetrahydrocannabinol (THC) — which is responsible for getting people high — can be toxic for pets. As the legalisation of cannabis for people has spread nationwide, veterinarians have seen an increase in pet emergency room visits after dogs and cats have ingested the substance. CBD’s medicinal properties are wide-ranging and the apparent benefits can be summed up with the acronym PAINS —Pain, Anxiety, Inflammation, Nausea and Seizures. Most research focuses on pain, including three recent studies that found that dogs suffering from arthritis seem to be in less pain and move more quickly after taking CBD. Still, the scientific evidence of cannabis use in animals remains limited, according to the American Veterinary Medical Association. While findings from a few well-controlled studies have been published, much of what is known is related to anecdotal or case reports or has been collected from studies related to use in humans. Using cannabis in human medicine is more extensive than in veterinary medicine. People use it to ease chronic pain, alleviate chemotherapy-related nausea and manage symptoms associated with other conditions, such as epilepsy, multiple sclerosis, Alzheimer’s disease, Parkinson’s disease and HIV/AIDS.
Further complicating matters, CBD can be extracted from the federally legal hemp plant, which the federal government defines as cannabis containing less than 0.3 per cent THC. (A pre-rolled joint sold in a dispensary typically has 15 per cent to 30 per cent THC). Hemp-derived CBD products are sold online across the country. However, these products are not subject to the same quality and safety requirements as recreational and medical cannabis produced within state markets. There is no easy way for consumers to know if they have the amount of CBD advertised, or if there are unnamed and potentially toxic compounds.
Marijuana, like heroin and LSD, is classified at the federal level as a Schedule I drug. This means it has been considered to have no accepted medical benefit and a high potential for abuse. Schedule II drugs have medical uses but high abuse potential. Examples include fentanyl and methadone. Should marijuana be downgraded to Schedule III, its perceived potential for abuse would fall to “moderate or low” for physical and psychological dependence. The recommendation was based on a Department of Health and Human Services review done under a directive from President Biden, who wants to keep people caught with small quantities of the drug out of the criminal justice system. The Drug Enforcement Agency (DEA) is reviewing the proposal to reschedule cannabis. The timeline for the agency’s decision is unknown. If enacted, the downgrade would more closely align the federal government with the 42 states and other jurisdictions that allow medical use by people. For recreational use, legal in 26 jurisdictions, a Schedule III drug would remain illegal federally but likely be a lower enforcement priority.
Cannabis-related drugs approved by the FDA for human use are dronabinol (brand names Marinol and Syndros), which has synthetic THC; nabilone (brand name Cesamet), which has a synthetic THC-like active ingredient; and Epidiolex, which has CBD derived from plants. These drugs are usually more expensive than non-approved ones, encouraging pet owners to look to the unregulated market. (The WebMDRx website shows a 1,000-mg bottle of Epidiolex priced around US$2,000). The pathway to legal use of cannabis in veterinary medicine will likely be a slow progression, punctuated by small steps. Unfortunately, the proposed DEA rescheduling will not affect most clinical veterinarians now.
Reclassifying cannabis likely would make it easier for research into the benefits and risks associated with cannabis use, arming veterinarians with more knowledge. A federal change might also soften the position of those state veterinary boards that still take an absolutist stance.
More extensive change already has been at the state level. Nevada in 2021 became the first state to let veterinarians recommend and administer cannabis. Before that, in 2018, California was the first state to explicitly protect veterinarians from disciplinary action if they discussed cannabis with clients. California lawmakers went further in 2022, voting unanimously to prohibit disciplinary action against licensed veterinarians for recommending cannabis (unless they are employed by or have an agreement with a cannabis business). That law requires the state Department of Cannabis Control to develop standards for veterinary cannabis products by July 1, 2025. Until those standards are established, veterinarians in America’s biggest state may not administer or sell cannabis products for pets — veterinarians can only recommend them. Only two other states have adopted laws explicitly letting veterinarians discuss veterinary use: Michigan in 2020 and Utah in 2022.
Rhode Island has taken a far more conservative stance. Twice, it has not passed a medical cannabis bill for pets due to concerns about toxicity expressed by the Rhode Island Veterinary Medical Association. “Medical marijuana products are toxic and of no clinical use,” the association states on its website. “Having pets get ‘high’ on these products is dangerous and considered animal cruelty.”