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April 14, 2021 – The proliferation of marijuana and similar products in the last decade has led to a dramatic increase in reports of accidental exposure in pets. It’s important for owners to know about this growing problem, and to learn to recognize the signs of toxicity and what to do in case of accidental ingestion or overdose.

Cannabis 101 – the basics

Tetrahydrocannabinol (THC) is the primary psychoactive component found in marijuana and cannabidiol (CBD) is the primary nonpsychoactive component of marijuana. In addition, there are synthetic cannabinoids (SCB) much more potent than traditional marijuana and these are associated with more severe clinical signs in exposed pets.

Interestingly, marijuana was occasionally used in veterinary medicine until 1937, when the first of several laws that penalized veterinarians for prescribing the drug was passed. Subsequent legislation criminalized use and possession.

Despite these legal restrictions, interest in the medical properties of marijuana continued. Studies teased apart the chemical composition of marijuana (these compounds are called cannabinoids) and identified specific receptors within the human body for these chemicals. In addition, scientists discovered that humans (and many animals) produce cannabinoids within the body (endogenous cannabinoids) forming the endocannabinoid system. The endocannabinoid system is involved in many bodily processes (via cell receptors) including:

  • Sleep
  • Mood
  • Appetite
  • Memory
  • Pain perception

The location of endocannabinoid system receptors might not be a surprise when we consider some of the purported medical benefits of cannabis-derived products (as well as the psychoactive effects). The list also gives us insight into the signs of toxicity.

Signs of toxicity

The clinical signs associated with marijuana and THC exposure most commonly reported by pet owners and veterinarians include:

  • Lethargy
  • Mental dullness and depression
  • Unsteady gait
  • Vomiting
  • Urinary incontinence or dribbling
  • Increased sensitivity to noises or movement as well as touch
  • Excess salivation
  • Pupil dilation

Less commonly reported signs include agitation, aggression, seizures or coma.

Many of the clinical signs of marijuana and cannabinoid toxicity are similar to other types of toxins except for one – a sudden onset of urinary incontinence. The presence of urinary incontinence can be an important clue for owners (and veterinarians) that a pet was exposed to marijuana or THC.

Cannabidiol, or CBD, is rarely associated with any clinical signs in cases of accidental exposure or overdose. Lethargy and depression, staggering and agitation were the most common problems noted by owners in these cases.

The good news is that fatalities are rare for pets ingesting marijuana, THC products or CBD products. Some pets need hospitalization for supportive care, but the vast majority of pets recover uneventfully.

It is important for owners to seek veterinary care in cases of known ingestion or if a pet is acting strangely without a known exposure, since many of the clinical signs associated with marijuana/THC/CBD toxicity can mimic more serious types of poison exposure.

Diagnosis and Treatment

No easily accessible tests for marijuana/THC/CBD/SCB are available for veterinary screening. The human urine drug screening test isn’t reliable for use in pets. More advanced testing can be used, but it’s costly and not easily available.

Unless there is a known exposure, diagnostics often focus on ruling in or out other toxicities with similar signs, including alcohol, ethylene glycol (anti-freeze), illicit drugs and ingestion of human medications such as opioids, tranquilizers or sedatives and antidepressants.

Treatment is based on clinical signs that are present and the time elapsed from ingestion (if known).

Inducing vomiting is a potential treatment if the time from ingestion is within 60 minutes and the pet is alert. Activated charcoal can be given orally as well in these pets to bind any material in the stomach - again, this treatment should be only used in alert pets.

In pets that are depressed, lethargic and showing neurologic signs (and are therefore in greater danger of aspirating vomit into their lungs), supportive care is a better option.

As always, prevention is easier and better for your pet’s well-being. Keeping products intended for humans well out of the reach of pets is important. Owners need to be especially vigilant when it comes to edibles, which are highly palatable for our pets. Finally, owners should always consult with their veterinarian before giving a pet any cannabinoid product. While studies are underway investigating product use in pets, there is little scientific evidence as to the benefits (and possible side effects) of cannabinoids for cats, dogs and even birds. Until science catches up, proceed with caution with guidance from your veterinarian.