Emerging Toxicosis: Cannabinoids!

Emerging Toxicosis: Cannabinoids!

“Some Things Shouldn’t Be Shared”

By Dr. Gail Mason,
DVM, MA, DACVIM  Staff Internist, Portland Veterinary Emergency & Specialty Care

Canines are experiencing increased exposure to marijuana-containing products including cannabidiol, paralleling the greater access to these products by their owners. Marijuana is comprised of the dried leaves and flowers of the hemp plant (Cannabis sativa, C. indica). Cannabis is known to contain at least 480 distinct compounds, including the psychoactive component known as delta 9- tetrahydrocannabinol or THC. This is frequently incorporated into edible products such as cookies, brownies, candies, cereals, beef jerky, and marijuana butter. There is a natural variation in the potency of different marijuana plants and strains and thus THC content of these edibles can vary significantly. Cannabinoids interact with chemical receptors in the central nervous system as well as the immune system in humans and dogs.  Another cannabinoid chemical is cannabidiol, commonly referred to as CBD, which is considered medicinal rather than recreational in use. In humans, CBD is used to reduce anxiety, increase appetite, relieve nausea, and assist in the control of seizures and sleep disorders.

With the advent of the Covid-19 endemic, more people were acquiring dogs and spending more time with them at home. In parallel, veterinary emergency hospitals experienced a dramatic rise in cannabis intoxication in dogs. Marijuana intoxication generally occurs following accidental ingestion of marijuana plant-based material or marijuana edibles.

Symptoms of Toxicity
Symptoms of marijuana toxicity may mimic those of several other toxins such as ethylene glycol or antifreeze poisoning. The most common symptoms include lethargy, drowsiness, abnormal gait, vomiting, tremors, dilated pupils, abnormal heart rate, and urinary incontinence. Owners may frequently describe a so-called "startle response," where the dog seems so sleepy it starts to fall over. At the last minute, it “startles" and regains its upright position.  Dogs with marijuana toxicity generally show symptoms between 30-90 minutes after ingestion. It is crucial that owners provide all relevant exposure information to an attending veterinarian so that appropriate testing and treatment can be initiated. For instance, marijuana products in the form of butter or wax, and synthetic cannabinoids represent highly concentrated forms and thus increase the potential for toxicity. Veterinarians are not legally obligated to report such incidences to local authorities, so the owners can reveal all pertinent information without concerns for repercussions.

Diagnosis of cannabinoid toxicosis is generally made based on the presence of compatible clinical symptoms and supporting medical history provided by the owners. Over-the-counter human urine tests can detect the presence of marijuana metabolites, though these tests yield inconsistent results in canines. While a positive test result likely represents toxicity, a negative test does not rule it out. It is important to note that because THC is stored in body fat, the effects of toxic ingestion can linger for several days. Fortunately, most cases of cannabinoid toxicity are relatively mild to moderate in nature, though there is the potential for lethal intoxication or death from aspiration pneumonia.

Treatment of Cannabinoid Toxicity
Fortunately, most cases of cannabinoid toxicity are diagnosed as mild to moderate, requiring only standard supportive care for patient recovery.  If less than about 30 minutes have transpired since the cannabis has been ingested, the veterinarian may elect to induce vomiting. This method is generally not recommended if the patient is already showing symptoms of toxicity. Administration of activated charcoal by mouth is a useful treatment as it absorbs toxins within the gastrointestinal tract, thus reducing the ability of the body to absorb them. Intravenous fluid support and patient warming are also frequently instituted. Rarely, the presence of life-threatening symptoms requires the administration of oxygen therapy, anticonvulsant drugs, short-acting anesthetics, and critical care monitoring.

Side Notes
It is not surprising that as cannabis has become widely available, many owners are interested in its use for pets. Unfortunately, research involving cannabinoid use in pets is sparse. While many products may be safe and readily available, none have them have been thoroughly investigated for veterinary use. The FDA as a federal agency does not recognize any of these products as legal and thus their manufacturers are not required to demonstrate efficacy. Similarly, these companies are not required to actually contain the amount of active ingredients as advertised. Lastly, the American Veterinary Medical Association issued a statement that “under current federal and state law, veterinarians may not administer, dispense, prescribe or recommend cannabis or its products for animals.” None of the laws allowing for the legalization of cannabis use extend to pet use currently. Hopefully, this will become an active area of research for the potential benefits of such products for dogs. If you do choose to use such products, please share this information with your veterinarian as these products may interact with other medications.
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