Marijuana (Pot, Cannabis, THC) Exposure and Toxicity in Dogs

The legalization of marijuana for human medicinal treatment has increased exposure and toxicity in dogs. In fact, according to the Pet Poison Helpline, there has been a 448% increase in veterinary visits and calls to animal poison hotlines from marijuana exposure and toxicity.

Marijuana, also known as “pot,” is a psychoactive drug derived from the Cannabis plant that has been around for hundreds of years. The term marijuana most commonly refers to the tobacco product made from Cannabis leaves. There are two commonly discussed species of the Cannabis plant – Cannabis sativa and Cannabis indica. Cannabis is used for both recreational and medical purposes.

There are approximately 483 known compounds in the Cannabis plant and over 80 cannabinoids with Tetrahydrocannabinol (THC) being the most potent and psychogenic. The amount and concentration of each cannabinoid varies with the different plants and stains of plants. The concentration of THC found in plants is dependent on environmental conditions such as soil type, nutrients, elements, moisture, and exposure to light.

THC is present in the leaves and flowering tops of the cannabis plant. Hashish, another THC containing product, is the resin extracted from the plant. The second most commonly recognized cannabinoid is cannabidiol, commonly referred to as “CBD.” The difference between THC and CBD is that THC causes psychotropic effects (affect mentation), while CBD is felt to have limited toxicity and is not psychotropic.

The Cannabis plant is also known as “hemp,” but more commonly refers to strains with less psychogenic properties because of the minimal levels of tetrahydrocannabinol (THC). In people, THC is sometimes used to alleviate nausea associated with chemotherapy, help with muscle spasms caused by multiple sclerosis, to treat seizure disorders, and much more.

Learn more about the medical use and possible toxicity of CBD oil in Dogs.

Unfortunately, because of the illegal nature of these drugs and the concern over societal stigmas, diagnosis and treatment are often delayed. This brings up the point – what does your vet do if you bring a dog in with an illegal drug exposure? Learn the answer here.

How Does Marijuana Affect Dogs?

Some dogs will literally eat anything and can be exposed to marijuana by ingestion of cigarettes, dried leaves, or baked products containing marijuana. There are also reports of dogs eating human feces containing marijuana and second-hand smoke causing intoxication. Sometimes, owners intentionally give marijuana to their pets to “see what happens.”

Since legalization, new varieties and forms of the drug have made their way into the marketplace. Cannabis can be taken by ingestion capsule or ingested in various food products, including candy, suckers, cookies, brownies, butters, drinks, as well as by smoking or vaporizing. Absorption is enhanced by concurrent ingestion of fatty foods.

When inhaled or ingested, the THC enters the body and binds with neuroreceptors in the brain including norepinephrine, serotonin dopamine, and/or acetylcholine. This binding alters normal neurotransmitter function.

Signs of Marijuana Toxicity in Dogs

The most common side effects of marijuana intoxication in dogs are depression, lethargy, listlessness, loss of motor coordination or balance (stumbling), incontinence of urine, low heart rate, low blood pressure, low body temperature, respiratory depression, dilated pupils and glazed over eyes, vocalization like crying or whining, agitation, drooling, vomiting, seizures, and coma. Some dogs may experience hallucinations and have increased sensory stimulation to noises or fast movements.

The stereotypical dog that presents to a veterinary clinic for possible marijuana exposure is lethargic, listless, stumbling, glazed over eyes, may dribble urine, and hyper reacts to fast motions or noises in close proximity.

One danger with marijuana is that vomiting is common, and if the dog is profoundly lethargic and begins vomiting, aspiration of vomitus into the lungs can lead to severe breathing problems and even death. However, this is relatively uncommon.

The signs of exposure to marijuana in dogs can begin as quickly as 5 minutes to 12 hours after exposure with most showing signs within one hour. The effects can last from a half hour to several days depending on the amount and type of marijuana ingested.

How Toxic is Marijuana?

THC is readily stored in the body’s fat tissue including the liver, brain, and kidneys. The liver metabolizes it and much of it is excreted in the feces and urine.

The good news is that marijuana exposure or ingestion is rarely deadly and long-term complications are uncommon. Toxicity of marijuana in dogs is low. It takes about 1.5 grams of marijuana per pound of body weight to be fatal. Therefore, death from marijuana ingestion is not common. This may change with the production of higher concentration palatable products. The most severe problems relating to marijuana exposure or ingestion in dogs have been from high concentrations of medical-grade THC.

Diagnosis of Marijuana Toxicity in Dogs

Diagnosis of marijuana ingestion or exposure in dogs is often based on the physical exam findings and history of exposure. There are human urine tests to determine the presence of THC that can be used, but are not dependable in dogs, often producing false negative results.

Treatment of Marijuana Toxicity in Dogs

There is no antidote for marijuana. This means that the treatment of marijuana exposure usually involves trying to eliminate the drug from a dog’s system, treat secondary signs, and provide support until the drug is eliminated from their systems.

Treatments for marijuana intoxication in dogs may include:

• Induction of vomiting may be recommended to remove residual THC in the stomach. Medications used to induce vomiting may include apomorphine or hydrogen peroxide.
• Depending on the severity of the signs, some dogs may be administered activated charcoal to help absorb or bind any marijuana in their system.
• Medications may be given to control vomiting, such as maropitant or ondansetron.
• Intravenous (IV) fluids may be given to help eliminate the drug.
• In severe cases of marijuana toxicity, drugs may be needed to treat seizures and control abnormal heart rates.
• IV lipid therapy can be used in severely affected patients.
• It is important to protect dogs from injury or self-trauma during this time. Because of the range of signs, including agitation, lethargy, hallucinations, and incoordination, some dogs are vulnerable to falling or reacting abnormally to loud noises.
• The ideal environment for a dog with marijuana ingestion and toxicity is a quiet dark area in the house away from stairs, high furniture, sharp objects, and bodies of water (such as lakes, swimming pools) while the THC is being eliminated from their systems.

The vast majority of dogs exposed to marijuana fully recover within 24 hours. After ingestion, THC is rapidly absorbed, and generally, within 24 hours, most of the THC has been excreted.

Prevention of Marijuana Toxicity in Dogs

If you have marijuana in your home, please keep it out of the reach of your dogs. If marijuana is being smoked, keep all pets in a separate area with excellent ventilation until all smoke has dissipated.