As pet lovers, it is our primary goal to keep our furry friends happy, healthy and pain free. However, in a world of ever-changing trends, how do owners know what is best for their pets and what is just the newest health fad? Traditionally, veterinarians have been sought out to help guide these decisions but, in this changing climate, reliance upon Dr. Google is becoming more common – and vet visits are becoming less so. An increasing number of people are searching for natural alternatives to medications, and opting for diets for their pets that are grain-free, raw and antibiotic-free. Pet owners are also more commonly using their own homeopathic remedies. While these trends are mainly driven by consumerism and distrust in big pharma, the growing desire for at-home remedies can result in unsafe, unethical and even illegal outcomes.

Veterinarian Responses to Fads

Veterinarians must rely upon scientific research and laws as guidance. Fortunately, with two of the more well-known fads, scientific evidence is relatively cut and dry: grains are not evil and eating raw meat can cause a slew of health problems, such as contracting salmonella. However, when it comes to homeopathic remedies for fleas and ticks, joint pain, dry skin and even neurologic conditions, the evidence is much harder to come by. This is largely due to the lack of regulations on many products that consumers are using for remedies. There are no FDA regulations, for example, on essential oils, herbs or nutraceutical pills, meaning there is no regulatory body confirming what is on the label; therefore, nothing confirming what is in the bottle.

Despite the lack of FDA regulation and any associated concerns expressed by veterinarians, the desire to use natural derivatives is growing among pet owners. And, one specific derivative is getting plenty of press lately: cannabis.

Two Types of Cannabis Compounds

Cannabis, dating back 6,000 years, is the only plant genus that contains the molecular compounds called cannabinoids. The two most notable compounds are tetrahydrocannabinol (THC) and cannabinol (CBD). While poorly divided, taxonomically speaking, cannabis is easily divided into two broad types based on the biochemical make-up. These two divisions are commonly referred to as marijuana and hemp.

The U.S. Drug Enforcement Administration (DEA) classifies Marijuana as a schedule 1 drug, which falls in the same category as heroin and cocaine. Due to its recreational use, it is the more well-known of the two cannabis plants. Marijuana contains high amounts of THC, the psychoactive cannabinoid, and low amounts of CBD, the anti-psychoactive compound.

Hemp, on the other hand, is grown for its seed and fiber properties. Hemp has low levels of THC and high levels of CBD (at least when compared to marijuana). Unlike marijuana, it is not possible to get high off the hemp plant. In fact, you would die of smoke inhalation before reaching high enough levels of THC from hemp to achieve a recreational high. This is due to the low concentration of THC and the fact that CBD is the anti-psychoactive that blocks the marijuana high. Because of that, some people refer to hemp as “anti-marijuana.”

Industrial hemp usage is legal in the United States but, oddly enough, actually growing industrial hemp is illegal. In fact, since 1937, it has been illegal to grow any variety of hemp in the United States.  Under current law, imported hemp products are subjected to zero-tolerance standards for THC, even though the average amount of THC in marijuana is 20%, while the average amount in hemp is 0.3%. Somewhat illogically, the United States government does not distinguish between these two very different plants grown for completely different purposes.

Note About State Laws

In 2017, the number of states permitting industrial cultivation of hemp exceeded the number of states that have legalized medicinal marijuana (33 versus 29 to date). So far, though, few farms have begun cultivating hemp due to resistance from the DEA. This is because, while legalized in certain states, both marijuana and hemp are illegal federally.

Cannabis for Human Medicinal Purposes

So, what is it in these plants that has led to medicinal use? About 20 years ago, scientists discovered a system in the brain that responds to the compounds found in cannabis, specifically in marijuana. The system is called the endocannabinoid system and has been shown to play a role in the cardiovascular, digestive, endocrine, immune, reproductive and nervous systems. The discovery sparked interest in finding specific chemicals in marijuana that could be targeted to treat specific conditions. Since that time, research on medical marijuana has increased significantly but, with the schedule 1 classification, doing approved research is still difficult.

While there are plenty of studies that show promising results in treating conditions, in order to officially conduct research on cannabis, scientists must first get approval from the DEA and the Federal Drug Administration (FDA).  While such studies have shown that cannabis can help manage pain and muscle spasms in multiple sclerosis, as well as improve symptoms of schizophrenia and Tourette’s Syndrome, too few of the studies were controlled clinical trials with placebo treatments.

These results have been mirrored in the series of studies permitted by the DEA at the Center of Medical Cannabis Research, University of California San Diego. The conclusion of these 13 studies was broad but simple: “cannabis may be useful medicine for certain indications.” Many researchers worried about the risk to users, though, with some patients becoming addicted (10%) and others finding the effects “intolerable.”

FDA-Approved Marijuana Drugs for Humans

Despite the unanswered questions and research-related challenges, there currently are three FDA-approved drugs made from marijuana in the United States. Marinol and Cesament are used to treat nausea in chemotherapy and AIDS patients, while Epidiolex is used to treat children’s epilepsy. Furthermore, Sativex is a drug developed in the United Kingdom that has been approved in over 24 countries to treat muscles spasms from multiple sclerosis and cancer pain, and it may be approved in the United States soon to treat pain associated with breast cancer.

Cannabis-Based Products and Pets

Because of the clinical evidence performed to date and experimental evidence by marijuana users, who have self-treated successfully, it is no wonder that people want to use cannabis-based products to help their animals. Given how difficult it is to get research approved for cannabis use in humans, one can imagine the level of difficulty involved in performing cannabis research in animals.

The most commonly used cannabis products on the veterinary market for treatment of animals all contain CBD oil. CBD can be extracted from marijuana or hemp and has claims to treat numerous disorders, including behavioral issues,  seizures and pain. While many veterinarians would welcome a safe and effective new way to treat diseases like arthritis or epilepsy, lack of legality and solid clinical studies makes the situation uncertain.

Veterinary uncertainty, though, has not stopped an array of products from popping up on the market. At conferences, one can be bombarded by naturopathic vendors that appear reputable, making claims on their products that cannot be substantiated. This makes it difficult to differentiate fact from fiction and, unless veterinarians are up to date on the current AVMA and federal standards, they may be tricked into stocking these products at their practices.

In a study that that was performed by the Department of Clinical Sciences and College of Veterinary Medicine and Biomedical Sciences at Colorado State University, published in the Journal of the American Holistic Veterinary Medical Association (JAHVMA) and Scientific Report, veterinarians were assigned three objectives: find out which cannabis products pet owners purchased, their reasons for the purchase and if they perceived a difference in their pet while using the product. The results of this study included 632 pet owners (88.1% dog owners, 11.9% cat owners) who have purchased hemp products from an online site. Most of the dog and cat owners (77.6% and 81.8%, respectively) indicated that they use the hemp product for an illness or condition diagnosed by a veterinarian.

The most common conditions eliciting treatment in dogs included seizures, cancer, anxiety and arthritis. The illnesses or conditions treated in cats were comparable, with cancer, anxiety and arthritis as the most common. The most common side effects reported by both dog and cat owners were sedation and over-active appetite. When dog owners were asked about the perceived positive impacts of the hemp, they reported the highest impact in relief from pain (64.3%), followed by helping with sleep (50.5%) and relief from anxiety (49.3%).  Cat owners perceived the highest impacts as relief from pain (66%), followed by reduced inflammation (56.3%) and help with sleep (44%). This information supports the growing anecdotal stories of the effects of cannabis in pets. In addition, this information provides a platform for researchers seeking to perform clinical studies on not only the effectiveness of hemp but also the adverse outcomes associated with the use of hemp.

Interestingly, this study also surveyed pet owners about their disclosures to their veterinarian about the hemp products used. Just under half of the participants had spoken with their veterinarian about the product, with most indicating that their veterinarian responded positively (61.7%), some expressing no opinion (30.7%) and very few responding negatively (7.7%). While most veterinarians would agree that anything having a positive impact on your pet is, in fact, positive, in this case, it is still illegal. In a recent article by the AVMA titled “Cannabis: what veterinarians need to know,” the AVMA cautions pet owners against the use of chews, oils and nutritional supplements containing CBD, citing the FDA as its regulatory beacon.

Currently the FDA does not approve the use of marijuana or hemp in any form in animals because of the lack of evidence about the safety and effectiveness of the products. The DEA stated in 2017 that “cannabinoids are not found in hemp, except in trace amounts. Therefore, extracts that contain more than trace amounts of cannabinoids must be part of the cannabis plants that are defined as marijuana and regulated as a schedule 1 controlled substance.”

In all this legislation, it might appear that hemp is unfairly getting a bad name; however, the ASPCA poison control center has recently reported an influx of calls and claims that ingestion of hemp-based CBD products causes the same clinical signs as ingestion of marijuana (products containing THC). It is not known whether toxicity is due to quality control issues in unregulated products, differing metabolism rates of CBD, or varying amounts of CBD in products despite label claims. The most common clinical signs include ataxia, depression, mydriatic pupils, hyperesthesia and urinary incontinence. While rare, other signs include vomiting, tremors and seizures with multiple deaths reported due to aspiration. For this reason, the FDA and AVMA caution pet owners against using these products and the FDA has issued numerous warnings to companies that sell products containing cannabidiol.

Conclusion

Overall, studies indicate great potential for cannabis as a treatment modality. If research was less restricted, more safety and dosing studies could be conducted. This would likely help explain, and ultimately prevent, poison-related deaths and begin to address concerns.

What is important to remember is that pet owners aren’t the people who face significant consequences for trying these products. Although it is illegal to sell products containing cannabinoids, and illegal to purchase products containing them, the only parties as of now who have been threatened to be held legally responsible are veterinarians and the cannabinoid-producing companies.

Here is just one example of how a state medical board perceives veterinary use of cannabis-based treatments. The California Veterinary Medical Board states that, while marijuana is legal for adults 21 and over, cannabis is illegal for use in animals. They go on to say that “veterinarians are in violation of California law if they are incorporating cannabis into their practices” and, if the board received a complaint regarding treatment of an animal with a hemp- or marijuana-related product, they would be “obligated to conduct an investigation and take appropriate disciplinary action if the findings so warranted.”

In conclusion, the use of cannabis products for animals warrants the attention of veterinarians and researchers and could one day be a wonderful treatment modality, but it cannot currently be recommended or stocked by veterinarians. It is suggested that both the promises and perils of medical marijuana for animals point to the need for science-based education, regulation and research. So, while we all aim to do what is best for our patients, it is most appropriate to advocate for change while remaining within the confines of the law. It is possible that one day cannabis will be a legal and accepted treatment in the veterinary community, but many steps must be achieved before then.