Accidental THC Ingestion Continues to Dog Pets

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Casually discarded roaches or dropped bits of edibles, inside and outside homes, are increasingly being gobbled up by canines, with unpleasant results. The instances of dogs sickened from ingesting marijuana has more than doubled in recent years, according to the National Animal Poison Control Center of the American Society for the Prevention of Cruelty to Animals (ASPCA).  California leads the nation in reported cases.

Tetrahydrocannibinal (THC), the marijuana component that causes psychotropic effects, can make animals, due to their smaller size and lack of awareness of what’s happening to them, quite ill.

“In recent years we’ve seen an increase in cases in the Bay Area,” said Dr. Roger Helmers of the San Francisco SPCA, which is unaffiliated with the national organization, stating that on average his organization sees a few patients that’ve ingested marijuana each month. “But we haven’t seen a significant increase since marijuana was legalized in California, possibly because it was so accessible before legalization.”

Dr. Alina Kelman, of Berkeley Dog and Cat Hospital, noted the problem’s prevalence in the East Bay as well. “We are in Berkeley, so we see this quite often as an emergency. I would say at least once a week. I don’t think it’s getting any worse or better, but I’ve only been practicing here for about four years. I have only ever seen it in dogs, and once in a potbellied pig. Cats can be affected, but they are usually more careful about what they eat.”

Veterinarians don’t typically report instances of dogs being exposed to marijuana to regulatory authorities, not wanting to discourage communication with pet owners.  If a pattern is exhibited by a particular San Francisco household the case may be referred to Animal Care and Control. 

THC poisoning is usually attributed to unintended ingestion, according to ACC administrator Deb Campbell. “It would be difficult for us to build a case and arrest someone for cruelty/abuse pertaining to a pet ingesting THC. There would have to be good evidence that would give the DA’s office enough material to file charges.”

Helmers believes that marijuana legalization should liberate owners to be forthcoming about what’s happened to their dogs where they’re aware of it.   “If you think your pet has ingested marijuana, don’t be afraid to bring your animal in for treatment,” said Helmers.

“We see marijuana toxicity so frequently that we can usually identify it when the animal comes in the door,” said Kelman.  “If we are not sure, or if the owner vehemently denies any possibility of THC exposure, we can use a human urine drug test kit to try to prove exposure. A positive result is trustworthy, but we do often see false negatives, possibly due to differences in marijuana metabolites in dogs or because of running the test too early in the toxicity. If we get a negative and the owner says THC exposure is impossible, then we offer running full bloodwork to ensure nothing else is seriously wrong that could be causing the neurologic signs.”

Symptoms of THC exposure include ataxia – lack of coordination – dribbling urine, hyperesthesia – anxiety and overreaction to movement and interaction – sedation, refusal to eat or drink, a low heart rate, vomiting, and tremors.  The indications can be alarming, appearing as though the dog is having a seizure or stroke.  Animals can be confused and frightened. Stoned dogs will typically have lower or elevated body temperatures and other abnormal vital signs, such as low blood pressure and respiratory depression.  They often drift in and out of sleep, and have trouble getting up, stumbling about in a stupor when they’re upright.  Milder cases usually see a cessation of symptoms within 24 hours, but the effects can last several days. 

“We had one dog recently that was trying to bite his owner because he was so terrified and confused in his intoxicated state, so you have to be careful,” warned Kelman.

Although exposure through second-hand smoke can cause mild toxicity, edibles are usually involved in extreme cases, which can result in hospitalization. An intravenous lipid infusion can be used to bind the THC and clear it from the body at a faster rate.  Another possible decontamination method is to anesthetize the animal and pump its stomach.

Most cases don’t require hospitalization. If a short period has passed since the THC was ingested, inducing the pet to vomit is a common treatment course. If the animal already exhibits symptoms then doing so wouldn’t be helpful; the drug will have already been absorbed from the stomach, and the procedure poses a risk of aspiration.  If the dog is responsive and ambulatory, it can generally be treated as an outpatient with an anti-nausea medication injection to suppress vomiting and later aspiration, as well as to restore appetite as quickly as possible, and enable it to consume water.   A fluid injection can be given under the skin to maintain hydration in the interim. Sometimes activated charcoal is used to try to prevent further absorption of THC from the stomach, but this is a delicate procedure, as there’s a danger of the dog aspirating some of the charcoal during the process. The pet should be kept warm and comfortable, confining it so it won’t hurt itself while feeling the effects of drug exposure.

“The worst case I have personally seen was a dog that was sedate to the point of not being rousable and could not get up or turn himself,” stated Dr. Kelman.  “The owners could not afford to hospitalize the dog and took him home. He later developed aspiration pneumonia from laying on one side for too long while intoxicated. We were able to treat him with antibiotics and he survived. Brachycephalic dogs are at especially high risk of aspiration pneumonia.”