by Caroline Coile, PhD
Topper, a 7-year-old Ibizan Hound, could hardly walk after being diagnosed with severe arthritic changes due to Valley fever. “The pain became so debilitating he had to be carried outside to eat, drink, or use the bathroom,” recalls owner Christy Moore. “He was on pain medication but it wasn’t working. A friend recommended pet CBD. Within three days he could walk on all four legs and I was crying tears of joy. It was the miracle we needed.”
Lady Amelthia, a Greyhound, was so petrified of thunderstorms she would destroy a crate to escape. “Holding her only made her claw to get away. A ThunderShirt reduced her from 100 to 90 on the anxiety scale,” recalls owner Jenn Boswell, director of the Alabama Greyhound Adoption Center. “Veterinary-prescribed trazodone took it down to a 50. Tried three drops of CBD oil and it went down to a 5.”
Success stories abound of dogs overcoming anxiety, slowing seizures, and even beating cancer due to cannabidiol (CBD), one of more than 100 cannabinoids found in cannabis plants. But how can one substance help so many unrelated problems? Or can it?
Cannabinoids are substances including CBD and THC that mimic the endocannabinoid chemicals naturally produced in all vertebrates. Receptors for endocannabinoids are found throughout the body. The body’s endocannabinoids act as master regulators that signal other systems when to speed up or slow down, working to stabilize the body and return it to homeostasis. Cannabinoids from the cannabis plant affect these same receptors, each in slightly different ways. For example, THC causes a high, while CBD does not.
Is It Harmful?
Unlike THC, which can cause toxicity and even death in dogs when given at prescribed human dosages, the worst CBD has been documented to do is cause diarrhea and changes in some liver enzyme values after several weeks. The main concern with CBD is that it inhibits a chemical in the body called cytochrome P450 that is responsible for metabolizing most drugs. If a drug’s efficacy depends on its metabolized product, CBD could render it less effective. If a drug’s safety depends on it being cleared from the body within a certain time frame, CBD could cause it to build up to toxic levels. Never give your dog CBD without your veterinarian’s knowledge if your dog is taking other drugs.
Does It Work?
Research with dogs is still scarce, but there’s a huge body of research (about 23,000 published papers!) looking at CBD’s effect on laboratory animals and humans, with encouraging results for pain, especially arthritic pain, itchiness, anxiety, and cancer, all of which have at least one canine study as well. The results in dogs? It depends.
Arthritis: Several studies have looked at CBD’s effectiveness against arthritic pain, all with positive results. A Cornell University College of Veterinary Medicine study found dogs given CBD at a rate of 4.4 mg per pound twice daily for a month showed significant improvement in pain relief and quality of life. Lead investigator Joe Wakshlag, DVM, Ph.D., DACVN, said that some dogs were initially so decrepit that their owners considered euthanasia, but that after just days on CBD they were trotting around and even climbing stairs. A Baylor University study found similar improvement, adding that CBD worked better when delivered in a liposomal formulation.
Itchiness: Two recent double-blind, placebo-controlled dog studies report CBD significantly reduces itchiness. An Australian study conducted by the company CannPal found their CBD product reduced itchiness, inflammation, and skin lesions by 51 percent after eight weeks of treatment. An American study conducted by the company ElleVet found their product, which combines CBD with another cannabinoid, CBDA, significantly reduced owners’ reports of itchiness.
Cancer: Cannabinoids are reported to induce cancer-cell death and prevent metastasis. In a Cornell University study of CBD, dogs, and cancer, researchers found CBD along with a standard chemotherapy drug reduced cancer-cell proliferation in vitro more than the chemotherapy drug alone. Anecdotal reports from veterinarians have claimed CBD shrunk cancer cells or put dogs into remission.
Behavior: Anxiety, and especially noise reactivity, is a major reason dog owners seek help using CBD. But despite anecdotal reports of its effectiveness, no controlled study so far has shown it to be particularly effective. A study from the University of Western Australia may show promise for aggressive behavior. Shelter dogs with aggressive tendencies exhibited less aggression toward humans when tested after 15 days of CBD administration. In a study from the University of Kentucky, physiological measurements of anxiety in response to noise were not significantly different for CBD versus placebo, and were worse compared to trazodone (a drug commonly prescribed for anxiety). Note, however, that in this study the CBD was administered four to six hours before testing, which may have been too long a waiting period.
Seizures: Lots of anecdotal reports hail CBD’s success combatting seizures in dogs, but the single controlled study delivered moderate results. In this Colorado State University study, dogs given CBD for 12 weeks had 33 percent fewer seizures than those given a placebo, but it didn’t work for every dog. These researchers are now working on a larger trial using higher CBD doses. Note that THC has been reported to cause seizures, so it should never be included in any CBD product for seizure control. In addition, CBD’s effect on cytochrome P450 could interfere with prescribed anti-seizure drugs, so never use it without your veterinarian’s consent.
Other: There’s also evidence from laboratory animals that CBD is effective in promoting bone healing, fighting infection, treating inflammatory bowel disease, slowing degenerative myelopathy, quelling nausea, and relieving pain, but these have yet to be specifically examined in dogs.
How to Choose CBD For Dogs?
With hundreds of CBD products on the market, and little regulation of them, it’s not easy to know which is best. Look for a product with the National Animal Supplement Counsel (NASC) Seal of Quality Assurance, and one that has a third-party certificate of analysis that includes potency, lists all ingredients, and discloses the possible presence of heavy metals, mycotoxins, or pesticides. Avoid edible products formulated for human consumption, which often contain ingredients such as xylitol that are toxic to pets.
Choose products that include other cannabinoids and substances known as terpenes that are also in the cannabis plant. CBD seems to work best when it’s in conjunction with these rather than isolated. But avoid full-spectrum products that include THC.
Aim for about 0.1 to 0.2 mg per kilogram of your dog’s weight, given twice daily by mouth. Work up gradually, but beware that more is not always better with CBD, as sometimes the response is biphasic, meaning that it doesn’t work if you give too little or too much.
Is It Legal?
Many veterinarians are reluctant to suggest CBD, whether because they believe CBD is not yet sufficiently proven helpful or because they fear professional or legal repercussions. CBD products are not approved by the Food and Drug Administration for dogs, but neither are common supplements such as glucosamine or fish oil; nor the majority of human-approved prescription drugs routinely prescribed in veterinary practice.
While it is legal to sell hemp-derived products containing less than 0.3 percent THC, until recently the American Veterinary Medical Association did not approve of veterinarians suggesting any cannabis products, including CBD, for patients. Even now, the law is unclear enough that many veterinarians fear repercussions if something went wrong due to their suggestion of CBD.
While some veterinarians are hesitant to suggest CBD, almost all are eager to discuss it once you bring it up. Of course, some veterinarians are more versed in its pros and cons than others. The main concern is its possible interaction with prescribed drugs.
Overall, the evidence is compelling that CBD can help at least some conditions. The endocannabinoid system is the largest system in the body, and the least explored. Every year brings new discoveries—and new claims. It’s the beginning of a brave new world of health, but as with any new path, expect some wrong turns, dead ends, and false hopes. CBD is not a miracle drug, but it may be the miracle your dog needs.
by Caroline Coile, PhD