CBD: Forget the legal issues—does it work in veterinary patients?
Source: dvm360
Veterinarians are being bombarded these days by questions, requests, lofty claims, unrealistic expectations and patchy scientific information about cannabidiol (CBD) products for pets. Public demand is outpacing the research as clients increasingly gain access to these products and, on the advice of a neighbor or internet article, begin using them on Max and Maizy. It’s a bit of a free-for-all.
Several experts spoke at a recent 2019 Fetch dvm360 conference about their experience and knowledge of CBD, including some case-based information on its use in veterinary medicine. Robert Silver, DVM, MS, CVA, chief medical officer for Rx Vitamins and a practicing small animal veterinarian in Colorado, is seeing some trends and passed along what he recommends so far.
Dosage
Prior to recent studies, the generally accepted therapeutic dose range for CBD in animals has been 0.1 to 0.5 mg/kg twice daily, but you can go as high as 5 mg/kg twice daily, according to Dr. Silver and Cital. A Cornell study shows that dosing as high as 8 mg/kg is safe,1 but this is not very cost-effective or practical, says Cital, who notes that dosing has been updated to 0.1 to 2 mg/kg twice daily based on now-available canine and feline data.
Pain management
Lower doses of CBD are generally adequate for neuropathic pain, but higher dosages are often necessary for conditions causing chronic pain and inflammation such as osteoarthritis (OA), says Dr. Silver.
Dr. Silver has been finding 0.5 mg/kg twice daily to be effective, and he reports that other veterinarians also find lower doses to work well for painful patients. “It’s worthwhile to start at this lower dose, which may provide a successful outcome, in order to reduce the cost and amount of hemp extract to be administered,” he says. The use of CBD together with opioids may allow a reduction in opioid doses, as CBD indirectly stimulates opioid receptors, producing an opioid-sparing effect, he says.
Cancer
Cannabinoids appear to be able to fight cancer, possibly through the induction of cancer cell death, anti-angiogenesis and some anti-metastatic properties, these experts say. Cital reports that an in vitro study looking at three different canine cancer cell lines was just completed by Joseph J. Wakshlag, DVM, PhD, at Cornell University, with results expected out by 2020. Dr. Wakshlag is also working on a quality of life in vivo study.
While Dr. Silver cautions that many claims surrounding CBD and cancer are, so far, not based in evidence, he also says researchers have discovered the presence of receptors on tumor cells for cannabinoids. He knows of a veterinary oncologist who was treating a lingual mass using non- tetrahydrocannabinol (THC) CBD as a sole treatment (0.5 mg/kg twice daily). Six weeks later the mass was reduced to nearly nothing.
Another anecdote involved a dog named Olive with an appendicular fibrosarcoma whose owners did not want to amputate. Non-CBD-containing nutraceuticals were used first, with success, for one year, and then the tumor started to grow again. The patient was started on a 1:1 CBD:THC product, and within 90 days the tumor had shrunk dramatically. In another account, a dog with an undifferentiated nasal carcinoma with bone lysis was treated with a non-THC CBD product (0.4 mg/kg twice daily), and the tumor shrunk significantly over six weeks of treatment. The dog was still in remission 14 months later.
Seizures
However, Dr. Silver warns, “we are in the infancy of use [of CBD products] adjunctively with epileptic medications.” He describes a Colorado State University study of CBD for refractory epilepsy (2.5 mg/kg twice daily) in which some dogs experienced a 40% reduction in seizures—not a very impressive result, Dr. Silver says.2 A new study at a higher dose (4.5 mg/kg twice daily) is taking place now, but it’s too early to draw valuable conclusions. Still, he says, for uncomplicated seizures that aren’t frequent or are well-controlled with anti-convulsant drugs, veterinarians and pet owners are finding that 0.5 to 1.0 mg/kg of CBD twice daily can control seizures and, in some cases, allow for reduced doses of anti-epileptic drugs.
Future hopefuls
There’s lots of enthusiasm for the therapeutic use of hemp products, even those with THC, for medicinal human and animal use. Cital notes a long list of potential future usages, including eye drops for glaucoma, tumor injections, stimulation of bone growth, safe sedation for puppies and young animals, anesthesia induction, inhalers for lung cancer (CBD may have pulmonary cytoprotective properties), pain relievers from certain parts of the plant, antifungal and antimicrobial bedding for animals, treatment for chronic cystitis in cats, use for chronic dermatitis in dogs and cats, and treatment of inflammatory bowel disease, among others. Another use for hemp products is biowaste cleanup—they’re able to absorb pollutants from the environment and can be used to reduce the effects of greenhouse gases.
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