The use and advocacy of cannabis-based therapies has been a hot topic in the world of human medicine for some time. We frequently hear reports of proposed legislation to legalize cannabis-based products for medicinal and/or recreational use. With the increase in interest and awareness about the medicinal applications of cannabis, pet owners have shown a similar interest in its application for disease management in companion animals.
With the legalization of marijuana for recreational use in many states of the U.S. in recent years, veterinarians have also seen an increase in toxic exosures in companion animals. Toxicity is due to exposure to the pyschoactive constituent in marijuana - THC (tetrahydrocannabinol). Not all cannabis is alike, however. The Cannabis sativa plant has two main cultivars or strains - marijuana and hemp. In a recent VetVine Specialty Update on this topic we discuss their differences and the potential applications for hemp-based products in the management of diseases or conditions in veterinary patients.
Cannabinoids and Endocannabinoid System
Cannabinoids are chemical substances that are derived from 3 possible sources:
Cannabinoids cause their effects by binding to cannabinoid receptors in the body. These receptors are located in many different organ systems and tissues including the brain, spinal cord, skin, GI tract, heart, lung, immune cells, among many others.
The effects of cannabinoids depend on which cannabinoid receptors they bind to, and include inhibition of the release of some neurotransmitters (including dopamine, histamine, serotonin, GABA, among others), as well as modulation of various mediators of inflammation.
There are high concentrations of endocannabinoid (CB1) receptors in the brain and spinal cord - specifically in areas of pain modulation, movement, and memory processing. It is well-established that the endocannabinoid system plays a role in those activities as well as nervous system repair, inflammation, appetite, itchiness, cognition, anxiety, among others.
Therapeutic Potential of Cannabinoids
The therapeutic potential of cannabinoids is fairly well documented for humans. There is a moderate level of evidence that cannabinoids are beneficial for managing conditions associated with pain and spasticity. Cannabinoids are also helpful in managing the nausea associated with chemotherapy and have also shown benefit in other conditions including: epilepsy, asthma, inflammatory bowel disease, depression, glaucoma, Parkinson's Diease, among others. Interestingly, it's also been shown that malignant cancer cells have higher numbers of cannabinoid receptors, and that binding of those receptors can trigger cancer cell death.
In animals, there is much less evidence to support their use. In fact, scientific studies to support dosing recommendations and efficacy in companion animals are seriously lacking. However, there is a bit of anecdotal evidence that shows that cannabinoids benefit pets with anxiety, pain, arthritis, seizures, and itchiness. Studies in laboratory rodents have demonstrated the benefit of cannabinoids for a variety of diseases and conditions including cancer, cardiovascular disease, pain, asthma, vomiting, diabetes, and others. These findings warrant further investigation of the use of cannabinoids for treating companion animals with similar diseases.
Commercially Available Cannabinoid Products
In recent years, a number of cannabinoid products have become commercially available for use in pets. These products are orally administered (as edibles, capsules, oils), and are non-psychoactive products derived from hemp. It is generally recommended that dosing of hemp products should be started at the low end of the dosage range and to increase if desired effects are not seen. Check with your veterinarian for their recommendation and before beginning any supplement.
As to their effectiveness? Again, there is little out there. There is one recently published survey of pet owners that had used a commercially available hemp product in dogs and cats. The product was found to be moderately to very helpful in 49% to 64% of dogs for anxiety, sleep, and pain. In cats, the product was thought to be moderately to very helpful in 44% to 66% for sleep, inflammation, and pain.
It's critically important to remember that marijuana, products derived from marijuana, and synthetic cannabinoids high in THC content should not be given to companion animals, as THC is associated with toxicity in pets.
Cannabis & Commercial Products - What Veterinary Professionals and Consumers Need to Know
