- A growing number of pet owners are using cannabis-derived products containing high doses of cannabidiol (CBD) and low or negligible doses of THC to alleviate pain, seizures, and other conditions. But what’s known about the science of cannabinoid medicine and pets?
Unfortunately, not a lot. But there are a few things to be learned from the science of cannabis and dogs and cats, even as the field emerges from decades of neglect.
As with humans, the question of using medical cannabis to improve the health of a dog or cat is a complicated one. There isn’t a lot of solid, peer-reviewed research examining its safety or effectiveness. That’s slowly changing, though, and the science of cannabis and pets recently took a big leap forward. In July 2018, the first clinical studyexamining the effects of hemp-based cannabidiol on arthritic dogs was published in Frontiers in Veterinary Science, a leading international journal. The results were extremely encouraging.
That study, titled “Pharmacokinetics, Safety, and Clinical Efficacy of Cannabidiol Treatment in Osteoarthritic Dogs,” was led by Dr. Joseph Wakshlag of Cornell University. Wakshlag and colleagues measured the effects of a particular hemp-based cannabidiol product—ElleVet Sciences’ proprietary hemp oil blend—on pain and arthritis in a small sample of dogs.
The results were remarkable: More than 80% of the dogs in the study saw significant decrease in pain and improved mobility.
Few Other Studies
That’s only one study, though. As promising as it is, nobody should rely on a single study to decide on the right path for them and their dog or cat. And unfortunately, when it comes to pets and cannabinoid-based medicine, only a small number of studies have ever been published. (A search of the leading medical research databases turned up a grand total of four.)
Understanding the political, ethical, and scientific implications of using medical cannabis and hemp in animals is more urgent than ever, and there’s a lot to unpack.
Most Vets Can’t Touch CBD
You should know this up front: In most states, a veterinarian is not allowed to prescribe or recommend a cannabis product for your pet, regardless of the vet’s personal or professional opinion. Each state has its own veterinary board, and that board adheres to federal law concerning medical cannabis.
Even in California, where state law makes cannabis legal for all adults, the California Veterinary Medical Board clearly states: “There is nothing in California law that would allow a veterinarian to prescribe, recommend, or approve marijuana for treating animals. Veterinarians are in violation of California law if they are incorporating cannabis into their practices.”
Leafly spoke with Dr. Gary Richter, a veterinarian based in Oakland, CA, about this issue in 2017. At the time, Richter had mentioned an online petition he was working on to get a “compassionate care” law for animals in his state. Recently, Dr. Richter confirmed that a bill of this sort has recently passed through the state legislature and was signed into law by Gov. Jerry Brown.
“I’m happy to report it was signed on Sept. 29,” Richter said. “It goes into effect Jan. 1 next year. The bill was far from perfect but it is a huge step in the right direction and the first of its kind in the nation.”
Richter says he’s spent the last year in the political sphere, advocating to allow the use of medical cannabis for pets because he’s seen first-hand the benefits of its use. And yet, under current California law, veterinarians risk having their licenses revoked if they actively recommend a medical cannabis product to an animal’s owner.
“Almost anything that cannabis would be used for in a human, from a medical standpoint, has the potential to be equally as valuable in dogs or cats,” Richter said. “Pain, inflammation, arthritis, gastro-intestinal related things, stress, anxiety, seizures, cancer, you name it. We’ve seen the benefits in all of these areas. But if a vet talked about cannabis for pets, they literally did so at their own peril as far as the Veterinary Medical Board is concerned.”
Illegal States Are Tough
It’s even worse in states where cannabis is illegal for any purpose. For instance, contributing her own data to cannabis research has been almost impossible for Dr. Dawn Boothe, an internist and clinical pharmacologist at Auburn University in Alabama, according to an article published earlier this year in VINNews, the web site of the Veterinary Information Network.
“At Auburn University in Alabama, Boothe, the clinical pharmacologist, has had difficulty getting her clinical work off the ground, owing to the legal morass,” wrote reporter Edie Lau. “Alabama is one of 20 states where marijuana remains illegal for any purpose, although the state in 2016 created an industrial hemp research program overseen by its agriculture department.”
The DEA’s position on cannabis is clear: The agency holds that all cannabis-derived products, including CBD, are subject to the same restrictions as marijuana with substantial THC content. That means researchers are forced to jump through the additional hoop of applying for a federal permit to handle a controlled substance. Which makes it all the more difficult to conduct research on cannabis.
A Handful of Published Studies
As difficult as it is to research cannabis, a number of scientists have persevered and published solid peer-reviewed work. Their surprising results have piqued the interest of vets and pet owners alike.
“If my dog ever has chronic arthritis, this would be one of the things I’d definitely use.”
Until very recently, there was little-to-no data on the effects of cannabis in dogs. As recent as April 2017, American Veterinarian stated, “Concerning to many veterinarians is the lack of peer-reviewed clinical studies proving the efficacy of cannabis products for animals, yet another consequence of marijuana’s status as a controlled substance.”
The angle that has gotten the most vetting is that of marijuana’s toxicity to animals—in other words, dogs or cats accidentally eating their owner’s supply. Indeed, as far back as 2004, a study found that marijuana poisoning was possible in dogs, based on a milligram per kilogram, or weight proportionate, dosage.
That 2004 study found that “From January 1998 to January 2002, 213 incidences were recorded of dogs that developed clinical signs following oral exposure to marijuana, with 99% having neurologic signs, and 30% exhibiting gastrointestinal signs.”
The study in particular gauged what “poisoning” looked like in the animals. Researchers cited gastrointestinal signs as primarily vomiting, and neurological signs as depression, tremors, seizures, disorientation, hyperactivity, or stupor. Prior to this study, there were only a few surveys of cannabis-smoking teenagers who’d exposed their pets to secondhand THC.
Most Research Focused on Harm
Through the 2000s, there were only a few studies done on cannabis and dogs, all mostly corroborating the plant’s mild toxicity. The authors of a 2013 study conducted by a veterinary hospital in Denver the observed that “although the drug has a high margin of safety, deaths have been seen after ingestion of food products containing the more concentrated medical-grade THC butter.”
Even so, this recent Cornell study on cannabidiol and arthritis in dogs has given scientists an even deeper understanding of how cannabis works in the body of animals and by extension, humans, especially when it comes to absorption and dosage. And other studies currently underway, including several more by ElleVet Sciences and Wakshlag as well as by researchers at Colorado State University, are looking like they will take these new discoveries even further.
Dogs Absorb CBD Differently
Previous to this study on ElleVet Sciences’ hemp oil in dogs, the effects of cannabis in dogs had been measured by giving them pills on a fasted stomach. What that 1988 study found is that the form of CBD administered was poorly absorbed and did little to help the dog.
“ElleVet came to us and were looking for a [scientist] that was open to doing a pile of studies on oil absorption for their cannabinoid-rich hemp, for the molecule called CBD, and they also wanted to do a clinical trial if we could find that it would be absorbed well,” said Cornell’s Wakshlag. “We did an initial study for absorption in a handful of dogs and it seemed to be absorbed pretty effectively compared to some of the older literature that was out there, which was surprising.”
Wakshlag says it’s the oil base that accounts for the difference in result. As opposed to the previous studies where CBD was administered intravenously or as a powder in a gelatin capsule, the team at Cornell found that cannabidiol was more easily and fully absorbed with a lipid carrier, or oil base.
What About CBD Dosage?
Another big challenge when it comes to cannabis and pets is finding the right dose for each animal. For CBD-only products, like the hemp oil from ElleVet Sciences, if they don’t offer a sufficient amount of CBD or if the CBD isn’t well-absorbed by the animal, you won’t see any change in the pet.
Thus, for Wakshlag, dosage was a prime concern, especially because there are several companies distributing nutraceutical derivatives of industrial hemp for pets, despite little scientific evidence regarding how to safely and effectively dose a pet orally.
“The dosing [in our study] was basically modeled off of other doses that seem to have worked in a handful of studies in humans – somewhere between 1-5 mg per kg body weight,” said Wakshlag. “So, we chose 2 mg because we wanted to hopefully see a clinical effect and, number two, we couldn’t make it so that it was so expensive that it couldn’t be used. In the end, we chose 2 because that would be a pharmacologically effective dose, and it wouldn’t be so expensive that it would preclude people from actually using it or buying it.”