Cannabis Toxicity in Cats: THC Effects, Signs and Clinical Management

1. Pharmacokinetics: Why Felines are Sensitive to THC

$\Delta^9$-Tetrahydrocannabinol is rapidly absorbed across mucosal, gastric, and alveolar surfaces. Owing to high lipophilicity, THC distributes rapidly into adipose reserves, liver, and brain tissue.

Felines possess an exceptionally high density of cannabinoid CB1 receptors in the cerebellum, brainstem, and neocortex. Hepatic glucuronidation pathways in cats are distinctively slow, resulting in prolonged enterohepatic recirculation and biological elimination half-lives exceeding 24 to 48 hours.

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2. Common Routes of Exposure

Feline poisonings typically occur through:

• Direct ingestion: Chewing dried buds, joints, roaches, or licking discarded vape cartridges.
• Commercial or homemade edibles: Extremely potent baked goods containing concentrated canna-butter or infused oils that combine massive THC doses with toxic cocoa.
• Secondhand smoke and vapor: Dense smoke in poorly ventilated rooms readily intoxicates cats due to their small tidal volume and grooming of smoke residue from their fur.

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3. Clinical Presentation: Ataxia, Hypothermia & Incontinence

Symptoms manifest within 30 to 90 minutes post-ingestion:

• Ataxia and swaying: Inability to walk in a straight line, limb weakness, and knuckling.
• Urinary incontinence: Involuntary, passive urine dribbling—one of the most consistent clinical indicators of feline THC toxicosis.
• Autonomic dysfunction: Bradycardia or tachyarrhythmias, glassy eyes with bilateral mydriasis, and sluggish pupillary light reflexes.
• Severe hypothermia: Rectal temperatures often plummeting below 36.5°C (97.7°F).
• Bizarre behavioral responses: Vocalization, agitation interspersed with profound depression, and extreme startle responses to mild sound or touch.

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4. Diagnostic Triage and Honest Clinical History

Veterinarians rely heavily on physical examination and truthful owner history (veterinary teams maintain strict patient confidentiality and never involve law enforcement):

• Over-the-counter human urine drug test strips often cross-react poorly with feline specific cannabinoid metabolites, occasionally producing false-negative results.
• Crucial rule-outs include ethylene glycol toxicosis, head trauma, organophosphate exposure, and ivermectin neurotoxicity.

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5. Medical Stabilization & Intravenous Lipid Emulsion (ILE)

Treatment focuses on physiological stabilization:

• Decontamination: Induction of emesis is strictly restricted to asymptomatic, fully alert patients within 1-2 hours of ingestion to avert fatal aspiration pneumonia.
• Supportive care: Bair Hugger convective warming blankets, balanced IV fluid therapy to support renal perfusion, and quiet dark hospitalization.
• Intravenous Lipid Emulsion (ILE) Therapy: In severe intoxications featuring coma or intractable bradycardia, IV 20% lipid emulsion acts as a 'lipid sink', sequestering fat-soluble THC molecules from target receptors and facilitating accelerated recovery.
• Prognosis: Overall survival exceeds 98% when comprehensive supportive veterinary management is instituted promptly.

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Scientific Sources and References

• Meola, S. D., et al. (2012). Marijuana toxicosis in dogs and cats: 125 cases. J Vet Emerg Crit Care, 22(6), 690-696.
• Brutlag, A., & Hommerding, H. (2018). Toxicology of marijuana in dogs and cats. Vet Clin North Am Small Anim Pract, 48(6), 1087-1102.
• Fernandez, A. L., et al. (2011). Intravenous lipid emulsion as an antidote in veterinary toxicology. J Vet Emerg Crit Care, 21(4), 309-320.