Marijuana ingestion is one of the most common toxicities in dogs 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, finding and eating some 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 and most pets will make a full recovery within 24 hours. However, mild clinical signs can last for up to three to four days because the chemical is absorbed into fat.
How is it diagnosed?
THC can be detected in blood or urine but diagnosis is generally based on unmistakable clinical signs as well as history from the owner. 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 have another pot dog." I myself treat several of these toxicities a month.
More than 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. At higher doses, dogs can suffer from hallucinations with barking or agitation. Seizures, low or high heart rates, respiratory depression and possible progression to a coma can also occur.
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 usually make it an unsuccessful attempt.
Your veterinarian may also elect to administer activated charcoal, which will help reduce the amount of THC absorbed. Subcutaneous fluids are often given to help prevent dehydration during the recovery period.
If clinical signs are severe, the need for supportive care will be indicated and your pet may need to be hospitalized. Supportive care entails intravenous fluids, repeat administration of activated charcoal, general nursing care, and observation of temperature, heart rate and breathing. If higher doses are ingested, some animals require sedation with valium, and in very rare cases, may require mechanical assistance with breathing if respiration is severely depressed. This is uncommon, but I have personally treated one patient who required ventilator support (he went on to make a full recovery).
Will my pet recover?
Even in extreme cases, the vast majority of animals recover fully and death very rarely occurs.
The main take-away here: Do not withhold information from your veterinarian if you suspect or know that your dog may have ingested marijuana—even if you think that there is no possible way your pet could have gotten into it. 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.