Marijuana ingestion is one of the most common toxicities that I see on an emergency basis, and the post-exam conversation generally starts with the owner asking, "Do you see this often?" I just smile and say, "Well, this is Berkeley..."
Pets are most frequently exposed to marijuana when they ingest “tasty” baked products, eat the remains of marijuana cigarettes, or get into somebody’s “stash.” Dogs can also get into mischief while out on hikes and find some form of abandoned drug.
What is Marijuana Toxicity?
Marijuana is the dried leaves and flowers from the hemp plant (Cannabis sativa) and the active chemical is tetrahydrocannabinol (THC). THC is absorbed quickly into the bloodstream and signs of intoxication can be seen from within minutes up to 3 hours after exposure. The drug is eliminated quite quickly from the body, but it can be absorbed into fat, making signs last for up to 3-4 days. Most animals will make a full recovery within 24 hours. However, if clinical signs are severe, the need for supportive care from your veterinarian will be indicated.
How is it diagnosed?
THC can easily be detected in either blood or urine, however, these tests can be inaccurate and diagnosis is generally based on the unmistakable clinical signs as well as history from the owner.
Over 95 percent of the veterinary patients seen for marijuana ingestion are dogs, and almost all exposed animals will exhibit neurological signs. The most common clinical signs we see are incoordination, urine dribbling, drooling, low body temperature, and an increased response to stimulation. The signs are quite "textbook" and this is such a common occurrence that our receptionists have learned to pick them out, bringing these pets to the treatment area saying, "looks like we got another pot dog."
At higher doses, dogs can suffer from hallucinations with barking or agitation, seizures, low or high heart rates, respiratory depression, and can possibly progress into a coma.
How is it treated?
If a pet has recently ingested the marijuana (within 30 minutes) your veterinarian can attempt to induce vomiting to minimize the amount of toxin available to be absorbed. However, if it has been longer than 30 minutes since ingestion, the anti-nausea effects of marijuana can make it an unsuccessful attempt.
If your pet is showing clinical signs of marijuana toxicity, or it has been longer than 30 minutes, your veterinarian may elect to administer activated charcoal which will help reduce the amount of toxin absorbed.
If clinical signs are pronounced, your pet may be hospitalized for observation of temperature, heart rate, breathing, support with intravenous fluids, repeat administration of activated charcoal, and intensive nursing care if they are critical. When higher doses are ingested, some animals require sedation with valium, and in rare cases, may require assistance with breathing if respiration is severely depressed.
Will my pet recover?
The vast majority of animals recover fully following treatment and death rarely occurs.
The main take away message is to not withhold information from your veterinarian if you suspect or know that your dog may have ingested marijuana. Your veterinarian is not under any obligation to report these events, and this information is needed to appropriately treat your pet as well as avoid unnecessary (and expensive) diagnostic tests.