A growing number of owners pet use cannabis products containing high doses of cannabidiol (CBD) and low or negligible doses of THC to relieve their pain, seizures and other ailments. But what do we know about the science of cannabinoids and pets?
Unfortunately, not much. But there are some lessons to be learned from the science of cannabis with dogs and cats, even though this area has been neglected for a very long time.
As with humans, the issue of using medical cannabis to improve the health of a dog or cat is complex. There is not a lot of solid, peer-reviewed research that examines its safety or efficacy. However, this is slowly changing and the science of cannabis and pets has recently taken a great leap forward. As of July 2018, the first clinical study examining the effects of hemp-based cannabidiol on arthritic dogs was published in Frontiers in Veterinary Sciencea leading international journal. The results have been extremely encouraging.
The study, entitled "Pharmacokinetics, Safety and Clinical Efficacy of Cannabidiol Therapy in Dogs with Osteoarthritis", was conducted by Dr. Joseph Wakshlag of Cornell University. Dr. Wakshlag and his colleagues measured the effects of a particular hemp-based product, cannabidiol, on pain and arthritis in a small sample of dogs.
The results were remarkable: More than 80 % of the dogs participating in the study saw their pain significantly reduced and their mobility improved.
Few other studies
But it's just a study. No matter how promising it is, no one should rely on a single study to decide the right course of action for him and his dog or cat. And unfortunately, when it comes to pets and cannabinoid-based medicine, only a small number of studies have been published. (A search of the major medical research databases yielded a total of four).
Understanding the political, ethical and scientific implications of the use of cannabis and hemp for medical purposes in animals is more urgent than ever, and there is much to unpack.
Most of the research has focused on harm
During the 2000s, only a few studies were carried out on cannabis and dogs, all corroborating the slight toxicity of the plant. The authors of a study conducted in 2013 by a Denver Veterinary Hospital observed that "although the drug has a high margin of safety, deaths have occurred after ingestion of food products containing more concentrated medical grade THC butter.
Despite this, Cornell's recent study of cannabidiol and arthritis in dogs has given scientists a better understanding of how cannabis works in the bodies of animals and, by extension, in humans, particularly with respect to absorption and dosage. And other studies currently underway, including several conducted by ElleVet Sciences and Wakshlag, as well as researchers at Colorado State University, appear to be pushing these new findings even further.
Dogs absorb CDB differently
Prior to this hemp oil study in dogs, the effects of cannabis in dogs were measured by giving them pills on an empty stomach. This 1988 study revealed that the administered form of CBD was poorly absorbed and did not help the dog much.
"ElleVet came to us and was looking for a group of scientists who were willing to do a bunch of studies on the absorption of cannabinoid-rich hemp oil, called CBD, and they also wanted to do a clinical trial if we could find that it would be well absorbed," said the Cornell Wakshlag. "We've done an initial study for absorption in a handful of dogs and it appears that the molecule is absorbed quite effectively compared to some of the older publications that exist, which is surprising.
According to the Wakshlag, it is the oil base that explains the difference in results. Unlike previous studies where CBD was administered intravenously or as a powder in a gelatin capsule, the Cornell team found that cannabidiol was more easily and completely absorbed with a lipid carrier, or oil base.
What about the CBD dosage?
Another big challenge when it comes to cannabis and pets is finding the right dose for each animal. For products that are exclusively based on CBD, such as hemp oil from ElleVet Sciences, if they don't provide a sufficient amount of CBD or if the CBD is not well absorbed by the animal, you will not see any change in the animal.
Thus, for Wakshlag, dosing was a major concern, especially since several companies distribute industrial hemp nutraceutical derivatives for pets, despite the limited scientific evidence on how to dose a pet safely and effectively orally.
"The dosage [in our study] was essentially modelled from other doses that appear to have worked in a handful of human studies - between 1 and 5 mg per kg body weight," said Wakshlag. "So we chose 2 mg because we wanted to see a clinical effect and, secondly, we couldn't make it so expensive that it couldn't be used. In the end, we chose 2 mg because it would be a pharmacologically effective dose and it wouldn't be so expensive that it would prevent people from using it or buying it.
Taking into account the type of treatment and the dose, the results of medical cannabis in dogs and cats with various conditions have been very promising.
The recent study by ElleVet and Cornell showed that once the right dosage is determined for your pet, cannabidiol can improve arthritis pain. The study involved a small sample of only 16 dogs, all with chronic arthritis pain in the Cornell study, and each dog saw significant improvement.
"We had one whose owner was really willing to euthanize the dog and it was a last-minute test," said ElleVet founder Howland. "Once she was in the test group, the dog behaved very well and turned around completely. Almost two years later, she is still alive and well.
"I think we've really scratched the surface in terms of how this could be used from an overall pain perspective," said Joseph Wakshlag, head of the Cornell study. "If my dog has chronic arthritis, that would be one of the things I would definitely use.
Gary Richter's own dog, Leo, suffers from epileptic seizures that are the result of brain damage from a dog attack. After trying several pharmaceutical drugs, the Oakland veterinarian put Leo on a cannabis preparation. Richter observed a marked change. "Almost immediately, the frequency of his seizures decreased," he said in a blog article on his website. "He's gone from several seizures a week to one or two a month. »
Research at Colorado State University, one of the country's leading veterinary research institutions, is beginning to support this project. An ongoing study at the CSU is testing the use of CBD on dogs with epilepsy. In July, Stephanie McGrath, a neurologist at CSU's James L. Voss University Veterinary Hospital, published "promising" preliminary data from a clinical trial on CBD. McGrath plans to share more results from this trial and another CSU trial for osteoarthritis later this year.
Off-label uses are spreading.
In addition to research at the CSU and other institutions, there are increasing anecdotal reports of cannabis-based medications that also help dogs with behavioural and gastrointestinal problems.
"ElleVet is science-based, so we don't advertise the product being good for anxiety," said company founder Dr. Howland. "But it does have an anti-anxiety effect. We've had a number of veterinarians in Florida try it with some of their patients who really freak out during storms. We've had some amazing reports of dogs that have [previously] injured themselves or thrown themselves through windows during storms; it's really calmed them down. We've also seen results with irritable bowel, it's fairly well documented for humans of the anti-inflammatory effects and how it works for autoimmune disorders like Crohn's disease. This is an area we would like to study further. It's an excellent side effect.
Wakshlag and ElleVet intend to do more studies on different types of pain. Three studies at the University of Florida are scheduled to begin this fall, focusing specifically on cannabis in canine oncology and post-operative patients.
What about cats?
So far, cannabis seems to be useful for dogs. But what about cats?
Unfortunately, there is not a lot of data on cannabinoids and cats.
ElleVet is the only company that has carried out a long-term clinical and pharmacological study on cats using its own products. Otherwise, the available data focus on the toxicity of accidental doses of cannabis in cats.
ElleVet found her hemp blend useful for cats, but Howland pointed out that cats react differently to cannabis than dogs.
"Cats are definitely not small dogs," she said, "and they metabolize things very differently. Cats can't take any of the drugs that dogs take for pain. Their livers just don't tolerate it. If a human tries to help a sick cat with a canine painkiller, "it can get very sick. There are very few safe options for cats when it comes to pain. So we did a long-term safety study to determine that [our products] are safe for cats.
They found that for the treatment of anxiety, cats responded better to cannabinoid drugs than dogs. Cats also showed a decrease in pain due to arthritis and other problems like dogs. But the half-life of their hemp oil is only two hours in cats, which means they need a much higher dose more frequently than a dog of the same size.
Although research on cats is still lagging behind that on dogs, leading cannabis researchers intend to start studying cats for good. ElleVet, for example, is currently conducting a study on pain in cats and another to determine whether cannabinoid drugs help cats with chronic urinary tract infections reduce their anxiety levels.
Are you curious? Do your research
Many pet owners are curious about cannabis treatments for their sick companions. The market for CBD-based products for dogs and cats is booming. But Richter acknowledges that changing the attitude of health professionals towards the use of cannabis for medical purposes with pets is slow and difficult work, and will continue for the foreseeable future.
"We've seen the benefits of all these products," Richter said. "The science is there, but as is often the case in the medical community, there will be a sizable group of physicians who will refuse to accept these products until they are researched.
Nevertheless, he hopes that research will continue to show that cannabis is a positive medical option for the treatment of dogs and cats. For this reason, Richter and many others who have seen the effects of cannabis medicine on animals firsthand, see no point in waiting to start helping pets.
"While I am certainly a proponent of research," he said, "just because research doesn't exist doesn't mean you can or should ignore something that is completely obvious and right in front of you.