Marijuana in Vet Med: Responding to requests
I am not 100% sure what the right or wrong way to approach this is, but the requests come often. Maybe to me in particular because of the reports of benefit with epilepsy in people and children. So here is what I’ve researched and here is a quick summary of some legitimate points:
· It is illegal in the state of Colorado for a veterinarian to prescribe marijuana for animal use. I believe it is illegal in all states still.
· The active pharmacologic ingredients of marijuana are Δ-9 tetrahydrocannabinol (THC) and Canabidiol (CBD); the pharmacokinetics of these products in animals is incompletely understood.
· THC has psychoactive effects, CBD does not.
· In people, cannabis has been used to treat glaucoma, nausea, and vomiting (often chemotherapy related), anxiety, spasticity, peripheral painful neuropathy, and epilepsy. Nabiximols (Sativex®) is derived from plant extract, contains an equal THC:CBD and is approved for use in spasticity associated with multiple sclerosis. Nabilone (Cesamet®) and dronabinol (Marinol®) are synthetic THC compounds approved for use in the US for chemotherapy induced nausea and vomiting.
· Limited pharmacologic data in dogs suggest low bioavailability of CBD after oral administration due to high first pass effect in the liver. In one study there was no detectable CBD in the serum of 3/6 dogs administered 180 mg orally
· CBD is a strong inhibitor of the cytochrome P450s, and may thereby alter the metabolism of other liver metabolized drugs (Phenobarbital, Zonisamide, felbamate, etc).
· As of 2015, no scientific studies on the benefit of CBD in spontaneous or induced seizures in dogs was found.
· Anecdotal claims of benefit from CBD products for seizures in people/children abound
· There do exist some scientific studies that support the benefit of CBD for people with seizures, and some of the above mentioned applications
· “A report published Thursday (this past week!) by the National Academies of Sciences, Engineering and Medicine analyzed more than 10,000 studies to see what could conclusively be said about the health effects of all this marijuana. And despite the drug's increasing popularity — a recent survey suggests about 22 million American adults have used the drug in the last month — conclusive evidence about its positive and negative medical effects is hard to come by, the researchers say.”
· There also exist scientific studies in people and dogs demonstrating that administration of marijuana products (THC in particular) can cause an increase in seizure activity
· Since increased availability of legal forms of marijuana in Colorado, there has been a 4-fold increase in reported marijuana intoxication in animals
-Michael Podell (ACVIM-Neurology), Abstract from the 2015 ACVIM forum
-CVMA position statement on the topic of marijuana use in animals:
-Petepilepsy.com (website developed and run by ACVIM-Neurologist, also responsible for the content)