Medical Marijuana and Pets

By Dr. Bruce Little

Much has been written and discussed over the past two years about marijuana and other plant derived products regarding the use of these products in pets.  Since January 2017, records indicate that as many as 28 states and the District of Columbia have legalized medical marijuana. In addition, eight states and the District of Columbia have legalized recreational marijuana. 

Can Pets be Prescribed Medical Marijuana?

There are no FDA approved marijuana or hemp products for use in animals, and thus the legality of veterinarians recommending any unapproved products can be confusing. Even in states where marijuana is legal, it’s illegal for a veterinarian to prescribe marijuana for animal use. Furthermore, all discussions regarding any therapeutic regimen for pets should be consistent with a valid Veterinarian-Client-Patient Relationship, meaning the veterinarian must have examined the pet and made a recommendation based upon the health status of that pet.

There are literally hundreds of marijuana growers and dispensaries in the United States, most of which are regulated by newly enacted laws and promulgated regulations in those respective states and/or local municipalities. There are different kinds and concentrations of medical marijuana sold in pot dispensaries depending upon the source and the purpose for which it is intended. These dispensaries use purpose grown marijuana plants that are much purer and stronger in the active ingredient, tetrahydrocannabinol, or THC, which is the ingredient that produces the feeling of euphoria or a high. On the other hand, the hemp plant does contain cannabidiol, or CBD, which is a chemical compound that may alleviate pain in humans. Both tetrahydrocannabinols, or THC and cannabidiols, or CBD are cannabinoids. The United States government defines hemp as cannabis that measures less than 0.3% of the ingredient tetrahydrocannabinol, a threshold that allows its movement across state lines.

Although there has been some research done in human medicine utilizing both THC and CBD ingredients, none of these products have been tested in animals. Tests of the effects of these products on dogs or cats of different breeds or weights using controlled research subjects has not been accomplished to date. With more than 60 different active ingredients of THC in each marijuana plant, concentration of the cannabis will vary with plant variety, sex of the plant (female plants are more toxic), geographic location and growing season. Marijuana has been used in humans as an anti-emetic (controls vomiting), analgesic, anticonvulsant, muscle relaxant, appetite stimulant and to decrease intra-ocular pressure in glaucoma. While CBD oils may not produce the typical euphoria seen with THC in humans, it does affect the nervous system in mammalian species. The specific mechanisms and effects remain unknown. CBD products often indicate a hemp source, leading many to believe that the products are legally marketed when in fact they are not. CBD is promoted as having antianxiety antipsychotic, antispasmodic, antibacterial, and many of the same properties as the THC-containing marijuana products without the euphoric properties. However, none of these conditions have been tested or studied in dogs, cats, birds or rabbits who seem to be the most frequently effected animals seen in veterinary emergency rooms. Yet, both internet and store-front dispensaries freely market both marijuana products and CBD or hemp oils to pet owners to give to their pets.  

Hemp or CBD has not undergone the required scientific review to ensure its safety and utility for use in animal food and therefore has not been approved as an ingredient for animal food. Furthermore, potential safety concerns related to the presence of cannabinoids (including THC and CBD) still need to be addressed. The Food, Drug and Cosmetic Act, under Section 301 (ll) states, “it is prohibited to introduce or deliver for introduction into interstate commerce any food (including animal food) to which has been added a substance which is an active ingredient in a drug product that has been approved for which clinical investigations have been instituted and for which the existence of such investigations has been made public.” There are exceptions, however based on available evidence, FDA has concluded that none of these is the case for THC or CBD. FDA has therefore concluded that is a prohibited act to introduce or deliver for introduction into interstate commerce any food (including animal food) to which THC or CBD has been added.

Marijuana or hemp toxicosis is commonly due and dependent upon the eating habits of dogs. Most cases reported have occurred in young dogs due to their voracious eating of anything that comes into their space, although cases have been recorded in cats as well. “In the past, most pet exposures to marijuana were ingestions of plant material from baggies or joints (cigarettes). This has changed, and now edibles such as cookies, brownies and liquid infusions have become more prevalent in animal marijuana toxicity,” says Dr. Tina Wismer, a veterinary toxicologist at the Urbana, Illinois ASPCA Animal Poison Control Center. Dr. Wismer goes on to say, “through selective breeding of the marijuana plant THC levels have become higher than ever doubling over the past 25 years or so. This allows for concentrations of large amounts of oils and waxes to be concocted into various types of edible products. Another change has been the increase in marijuana butter-based edibles. THC butter is made by heating marijuana in butter to extract the lipophilic THC and using that butter to make baked edible products. Although cats will eat these baked products, most of the toxicity in animals from eating marijuana-laced baked goods are dogs.” 

Symptoms of Marijuana Toxicity

The symptoms of marijuana toxicity in animals are usually dose related. The amount of THC consumed coupled with the breed, size, age and state of health of the dog or cat will show extreme variability among different individuals. Patients with liver impairment may be more sensitive. Also, behavioral effects can start at low doses in all species and at all stages in life. THC can be absorbed through inhaling; therefore, second hand smoke from a pipe, cigarette or an e-cigarette can be a factor in the level of clinical signs after exposure in pets. This is especially evident in pet birds.

Oral consumption is the most frequent route of exposure to pets. Clinical signs may become noticeable in 30 to 60 minutes after ingestion and may last for up to 72 hours. The most common signs include incoordination, increased heart rate, dribbling urine, disorientation, vocalizing, vomiting, diarrhea, increased salivation and hypothermia (subnormal body temperature). Seizures, comas and low blood pressure, although rare, may occur in a few cases. As is the case in humans, marijuana toxicity may be biphasic in dogs and cats by showing euphoria at first followed by depression.

Treatment for Marijuana Toxicity

Treatment for marijuana toxicity in pets is mainly monitoring to see that vital signs stay within acceptable limits. Heart rate, blood pressure, and especially the body temperature should be constantly monitored. It may be necessary to administer intravenous fluids if dehydration occurs and administer tranquillizers if the animal is agitated, anxious or barking excessively. Try to minimize external stimuli by placing the animal in a quiet area with little interruption or handling. If comatose, rotate the body position at least every four hours. Many marijuana toxicity cases can be managed at home as an outpatient while in constant communication with your veterinarian.  They will usually sleep off a marijuana high; however, there is great concern among veterinarians about the increased concentration of many marijuana products and the presence of synthetic cannabinoids (CBD) that can come in extremely high concentrations exacerbating the clinical signs observed in some cases.

Because marijuana falls under the Schedule I drug classification by the DEA, it’s illegal for veterinarians to prescribe various ointments, salves and antidotes for marijuana treatment in pets. Marijuana isn’t approved for veterinary use and it’s illegal for veterinarians to prescribe medical marijuana for pets. The best treatment, as is usually the case in most conditions, is to protect your pets from exposure to marijuana products in the first place.  Keep your dog, cat or bird out of the room when smoking these products and keep the baked or infused products away from the pets and everyone should be happy. Here are some resources if you think your pet may have ingested or inhaled marijuana:

ASPCA Animal Poison Control Center http://www.aspca.org 888-426-4435

Pet Poison Helpline http://www.petpoisonhelpline.com 855-764-7661

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