In Colorado there has been an increasing incidence of canine marijuana intoxications since it became legalized for human medicinal use in 2000 and even more so since it became legalized for recreational sales in 2014. The plant Cannabis satvia contains a cannabinoid known as delta-nine-tetrahydrocannabinol (THC), which is the major psychoactive constituent. Most canine marijuana intoxications are accidental where the owner may or may not know about exposure; it is important to recognize these cases based on history and physical examination findings.
Clinical signs of marijuana intoxication typically appear within hours of exposure and commonly include depression, ataxia, mydriasis, ptyalism, hypersensitivity to motion or noise, excessive flinching, urinary incontinence and bradycardia.
Often a tentative diagnosis is made on history, signalment and clinical signs. Diagnosis may be supported with a cage side urine illicit drug screening test, however this is a human test that has not been validated in dogs and has been associated with false negative results.
Treatment is mostly supportive in nature. For early non-symptomatic exposure, gastrointestinal decontamination is the mainstay of therapy. This includes induction of emesis and administration of activated charcoal. THC does undergo extensive enterohepatic recirculation, so typically multiple doses of charcoal are administered during hospitalization. If administering activated charcoal, care must be taken as this can cause significant electrolyte abnormalities (hypernatremia). When sending this home, we typically use UAA gel because of its ease of administration, smaller volume and it is not associated with electrolyte changes.
If an animal is already showing clinical signs of marijuana intoxication, do not induce emesis or give charcoal as there is increased risk of aspiration pneumonia because of altered mentation.
Prognosis is generally favorable for marijuana intoxications; however there have been recent reports of deaths secondary to marijuana ingestion and severe respiratory depression. These fatal cases had ingested marijuana butter which has a significantly higher concentration of THC. In cases where respiratory depression and hypoventilation is noted, mechanical ventilation can be lifesaving and should be considered. Severe intoxications with marked neurologic signs or respiratory depression are associated with a worse prognosis.
At VCA Alameda East Veterinary Hospital, we have the ability to provide 24/7 critical care monitoring and mechanical ventilation to any of your patients that may require this.
References:
Fitzgerald KT, et al. Topics in Companion Animal Medicine 2013
Meola DA, et al. Journal of Veterinary Emergency and Critical Care 2012
't hesitate to contact myself, Angela, or Kelsi with any concerns or if you would just like to introduce yourself-we like that too! We hope to see you at one of our Case-Based Rounds or Lunch and Learns; and coming up this summer we will have an open house to introduce our new lobby!