Marijuana and CBD Toxicity in Dogs

Marijuana and CBD Toxicity in Dogs

Cannabinoids are the active marijuana-derived substances that have pharmaceutical activity. Over 480 relevant substances have been isolated.

The amount of each contained in a sample of marijuana leaves will depend on the subspecies of plant, how the leaves have been dried, the time of year the leaves were harvested, the age of the plant, and other factors.

marijuana plant

Marijuana, known by many names, is a popular recreational plant used both legally and illegally by millions worldwide. 

Marijuana consists of the dried leaves and tops of the Cannabis sativa plant while “hemp” is a term generally reserved for the stems. Marijuana is diverted into assorted consumable forms while hemp is made into rope, canvas, and other materials. Hemp plants are legal to sell so long as they contain less than 0.3% THC, the chief recreational cannabinoid of marijuana.  

The body has natural cannabinoid receptors in neurologic cells as well as in immune cells. Effects of cannabinoids are only partly through these receptors. Our bodies make natural cannabinoids as well. Cannabinoids can have assorted pharmaceutical effects: reduction in nausea, induction of euphoria, interference with short term memory and ability to filter insignificant information, increased appetite, antioxidant effects, anti-inflammatory effects, antibacterial effects, and more.

The psychoactive chemical that makes marijuana a recreational drug is delta 9-tetrahydrocannabinol, more commonly called THC. Regular marijuana is typically 1-8% THC while hashish, made from the flowering tops of the plant and their resins, can contain up to 10% THC.

Another cannabinoid chemical is cannabidiol, commonly referred to “CBD”, which is not considered recreational and is of a more medicinal nature. Cannabidiol has been used in human medicine to mitigate anxiety, improve appetite, relieve nausea, control seizures of certain types, and assist in sleep disorders.

Assorted CBD products are available for human use both online and through dispensaries. Some products are marketed for pet use though is not legal. 

Please keep in mind that while cannabinoids may have medical uses in companion animals, THC can be toxic. It is important not to confuse the two components of the marijuana plant.

Marijuana Intoxication in Dogs

dog on marijuana medication

The usual pet toxicity case involves a dog that has inadvertently eaten a stash of marijuana. In dogs, clinical signs typically begin 30 to 90 minutes after the marijuana has been eaten. Because THC is stored in the body’s fat deposits, the effects of marijuana ingestion can last for several days.

Even more concerning is the increasing popularity of gummies, which contain higher concentrations of THC and is tastier and more enticing to pets.

Symptoms of toxicity 

Signs include: incoordination and listlessness along with dilated pupils, slow heart rate and sometimes urinary incontinence. A characteristic startle reaction has been described where the pet appears drowsy and even may begin to fall over but catches balance when a visual stimulus is noted.

Marijuana toxicity can look similar to intoxication with numerous other sedatives, but the most serious consideration is anti-freeze poisoning, which looks similar in its early stages and is usually fatal if not diagnosed early.

If ingestion has occurred, it is important that all the relevant exposure information to be given to the veterinarian; veterinarians are not obligated to report anything to local police.

If you know marijuana (or another substance) was involved in an intoxication, please tell the attending doctor. For most veterinarians, the primary concern is not the legality of the drug but helping your pet.

Urine testing similar to that done with humans can be done in dogs to help diagnose marijuana intoxication if the source is unknown. Test kits are available at most drug stores and can include assays for a number of recreational drugs. 

A relatively large volume is needed to run these tests, so if the pet is small this may be difficult to obtain, particularly in a female.

Also, false negatives are common when the THC urine test is performed on pet urine; a positive is confirmatory but there are many false negatives as the metabolites relevant to the test are different between dogs and humans. In most cases, the diagnosis is made based on the clinical presentation of the dog plus history of marijuana exposure.

Treatment

If less than 30 minutes have passed since the marijuana has been eaten it may be possible to induce vomiting, but after symptoms have started the nausea control properties of the cannabidiol make it difficult to induce vomiting. Furthermore, if the patient is extremely sedated, vomiting can be dangerous as vomit can be inhaled and cause a serious and deadly aspiration pneumonia.

Activated charcoal is a liquid material used in the treatment of poisoning. Activated charcoal is given orally and as it passes from one end to the other, toxins are trapped in the charcoal so that when the charcoal passes from the patient, the toxins pass too. 

Fluid support and keeping the patient warm may also be needed. If the patient has lost consciousness, then more intense observation and support is needed.

The chance of fatality is statistically small but possible. Depending on the severity of the signs, supportive care such as intravenous fluids and warming efforts can be used to keep the patient stable until the THC wears off.

Medical Marijuana Products for Pet Use

As medicinal marijuana becomes legal and commonplace in the U.S., many people wish to try products on their pets. Some cannabinoid companies even make products packaged for pet use.

There are several reasons to be cautious about using these products. Here are some to consider:

  • The FDA, being a federal agency, does not recognize any of these products as legal and thus their manufacturers are not required to show them to be effective. Similarly, they are not required to actually contain the amount of active ingredient they claim to have. (In several studies, numerous CBD oils were found to contain no CBD at all.
  • Cannabinoids are famous for intolerance effects. This means that an effective dose quickly becomes ineffective as the body becomes tolerant to the medication and more is needed to generate the desired effect. A cannabinoid that seems to create a good effect at first, is not going to be useful later on. How long does it take for a dose to become ineffective? No one knows but there was a study showing that with regular use, a toxic dose is no longer a toxic dose after one week.
  • It is not legal for veterinarians to prescribe any of these products: THC and CBD are not legal for veterinary use. And none of the laws allowing for legalization of marijuana use extend to pet use. Pet use of cannabinoid is not legal with only a few exceptions and these are with hemp products.
  • Research involving cannabinoid use in pets is still being investigated. Until more repeatble studies have been completed and approved products (with known concentrations) come to market, proper regimes for pets are not available.
  • While some CBD products may be safe and available, none of them have been formally investigated for pet use in the same way that FDA approved medications have been. If there is a product that actually has been proven effective and is available through your veterinarian, you may get better results from a more mainstream treatment plan.

Cannaboids will interact with other medications so if you plan to use any of these products, be sure your veterinarian is aware that you are doing so. Keep any medicinal or recreational products out of the reach of pets and children.

About the author: Hilary Granson

Hilary Granson, DVM, is a graduate of Cornell University College of Veterinary Medicine who lives in Houston, Texas. Dr. Granson opened Urban Animal Veterinary Hospital to address the needs of the community. Her favorite aspects of veterinary medicine include internal medicine, anesthesia, pain management, emergency medicine, and immunology. In addition to cats and dogs, Dr. Granson has experience treating avian and exotic patients. In her free time, she enjoys motorcycle riding, target shooting, finding good restaurants, and attending concerts. She has been published in veterinary and human medical peer-reviewed journals and writes for the Texas Veterinary Medical Association.

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