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Are Your Clients Considering Cannabis for Their Pet?

In recent months there has been a growing number of cannabis products marketed for pets, leading to discussions regarding the possible benefits these products may have for their health and wellbeing.  

If your client has indicated that they are considering, or already are using cannabis to treat their pet, we encourage you to engage them in further discussions in order to maintain an open and honest, trusting relationship that will ensure patient safety and maintain complete medical records.

The CAVCM has put together some tips to assist you in maintaining open dialogues while providing credible information to your clients.


What is the legal status of using cannabis for pets?

With the Cannabis Act having come into effect on Oct. 17th, 2018, all Canadian adults can legally purchase cannabis products through a licensed retailer or licensed producer. Although there is nothing that legally prohibits people from administering cannabis to their pets, it is important to know that there are currently no cannabis products approved for use in animals (other than hemp products that do not contain any phytocannabinoids).  

All phytocannabinoids, including THC and CBD, regardless of its source, have been added to the Prescription Drug List.  These products, therefore, require Health Canada approval and a Drug Identification Number (DIN) to be sold legally outside of the routes permitted under the Cannabis Act.

Those products currently being marketed and sold in Canada for use in pets are operating outside of the current legislative framework.


Is there any research to support using cannabis for pets?

Although there is limited published research assessing the clinical efficacy of cannabis in pets, there is ample research examining various medical conditions and treatments in humans and as well as extensive research in laboratory animals that have been published. A variety of references are available on the CAVCM website. (https://www.cavcm.com/resources-for-veterinary-members)


Is cannabis safe?

There has been a lot of attention regarding the risks of cannabis ingestion by pets, mostly focusing on the risks of THC intoxication.  This focus has been due to the high rate of occurrence of THC intoxication in dogs following ingestion of edibles or other sources of cannabis.  

However, despite a large number of reported cases reported involving THC ingestion, almost all cases recover uneventfully with appropriate supportive treatment.  In the most severe cases, secondary complications such as aspiration pneumonia can occur.

Cannabis combined with other drugs, or added to baked goods containing co-toxins, can pose increased risks and more challenging diagnosis and treatment.

All cannabis products sold through the Cannabis Act are required to follow Good Production Practices, test for contaminants (microbes, pesticides, heavy metals, and solvents), and label their products clearly with both CBD and THC concentrations.


What are the most common side-effects of cannabis use?

Recent studies examining the use of cannabidiol (CBD) in dogs has shown it to be generally well-tolerated.  The most common side effects reported include sedation, diarrhea, and increases in ALP (not associated with increasing Bile Acid values).  Overall, it has a wide safety margin.

The WHO report on CBD states that CBD has no effect on a wide range of physiological and biochemical parameters, or significant effects on animal behaviour unless extremely high doses are administered (eg, in excess of 150 mg/kg IV as an acute dose or in excess of 30 mg/kg orally daily for 90 days in monkeys).

Products containing THC require more vigorous oversight and cautious administration as the risk of adverse effects is greater.  The most common side effect reported is sedation, with possible ataxia and sensory hypersensitivity. As is commonly seen in humans, appetite stimulation can also be seen and is often a beneficial side-effect in patients with reduced appetite.  Some patients may also exhibit anxiety, although this effect can be minimized by using appropriate dosing and products with a suitable combination of CBD and THC.

What are the signs of THC intoxication?

THC intoxication is commonly observed as ataxia, lethargy (or sometimes agitation), disorientation, dilated pupils, urinary incontinence, hyperesthesia, and less frequently, tremors/seizures and vomiting.  Changes in vital signs including bradycardia, hypothermia, and hypotension can also be seen. In extreme cases, patients may present comatose.

Common signs of intoxication, in combination with urinary incontinence, has often been a subjective diagnostic tool for THC toxicity.  A paper published in the Journal of Veterinary Emergency and Critical Care (2012) reported only 47% of THC toxicity cases actually present with urinary incontinence, reminding veterinarians that the lack of incontinence should never rule out THC toxicity as a possible differential diagnosis.


How do clients find a reliable product?

Several factors should be considered when assessing a product.  A handout for clients is available at https://www.cavcm.com/resources-for-pet-families that expands on many of these points.  

Below is a list of some of the most important considerations when evaluating a product that a client brings in:

  • Is it legal?

  • Is it safe?

  • Do I trust the company?

  • Is the formulation appropriate for the patient?

  • Does it contain an appropriate cannabinoid/terpene profile?


What dose should clients start with for their dogs/cats?

At this time, most provincial regulatory bodies are cautioning veterinarians against providing outright dosing recommendations to their clients.  This is due to the fact that there is very little published research to support an appropriate dose of any given product.

However, when clients have chosen to use cannabis product with their pets, it is paramount that veterinarians ensure the safety of their patients.  

An important component of patient safety is understanding the range of doses that have been used both anecdotally, as well as in the published studies to date.

The majority of data has come from products that contain predominantly CBD, where anecdotally doses in the range of 0.1-0.5mg/kg BID are most common.  In the two studies published in 2018 using CBD products for dogs, CBD doses of 2 mg/kg BID and 2.5 mg/kg BID were used, respectively.

THC dosing is a little trickier as we currently have no published data on dosing, other than old research showing that a dose of 0.5mg/kg THC given intravenously was required to show signs of intoxication in dogs.

We do have a recently presented study that tested two products; one with 0.12mg/kg THC with 0.24mg/kg CBD, the other with 0.12mg/kg CBD with 0.24mg/kg THC.  These products were administered as a single oral dose in beagles.  None of the dogs in that study showed any evidence of adverse events or psychotropic changes, supporting the doses reported frequently in anecdotal cases.

Some practitioners have used a guideline of 0.1-0.25mg/kg for calculating a dose of THC, while others will calculate a ‘target dose’ of 0.4mg/kg TOTAL CANNABINOIDS.  

This provides a ‘target dose’.  When starting it is suggested to begin at ¼ of the target dose given once every 24 hours, and gradually increase dosing to target dose BID.

That said, there is a wide range of individual responses and sensitivities, so the golden rule of START LOW, GO SLOW definitely applies.

Are there potential drug interactions or contraindications?

In addition to the cumulative sedative effects that can be seen with other narcotics and sedatives, both CBD and THC are involved in cytochrome P450 metabolism which can affect the metabolism of multiple drugs.  Human studies have shown that the use of CBD can significantly alter the serum levels of many anticonvulsants, so close monitoring, when available, is recommended for drugs with narrow safety margins.

Other drugs, such as acetaminophen and NSAIDs can affect the endocannabinoid system, but clinically appear to be well tolerated in conjunction with CBD products.

The use of cannabis products should also be considered carefully in immature animals, breeding animals, and those with severe heart, liver, or kidney disease until further studies are done.


What type of monitoring should be recommended?

As the area of veterinary cannabinoid medicine is relatively new, and data on using specific products for specific conditions is often lacking, it is recommended that prior to beginning any cannabis-based therapy a pet undergo a complete physical examination. This would ideally also include a complete blood count and biochemical profile as a baseline, followed by repeat blood work 3-4 weeks after reaching target dose, and then every 3-6 months thereafter.  It is also recommended to have clients maintain a diary or logbook to track their pet’s progress.  A copy of a sample logbook page can be found at https://www.cavcm.com/resources-for-pet-families.


Remember, we should ALWAYS be a pet owner’s first line of information regarding the health of their pets!