Feline Rodenticide Toxicity Study Guide

Overview and Clinical Importance

Rodenticide toxicity represents a critical emergency in feline medicine, requiring rapid identification and species-appropriate intervention. Unlike dogs, cats are exposed through both direct ingestion of bait and relay toxicosis (consuming poisoned prey). Four major categories of rodenticides exist: anticoagulants, bromethalin, cholecalciferol (vitamin D3), and zinc phosphide. Each has distinct mechanisms, clinical presentations, and treatment protocols. Cats demonstrate unique sensitivities, particularly to bromethalin, making accurate rodenticide identification essential for successful patient management.

Rodenticide Classification

Board Tip - Memory Aid "ABCZ": Anticoagulants (only one with antidote!), Bromethalin (neurotoxin - cats MOST sensitive), Cholecalciferol (Calcium goes up!), Zinc phosphide (gas release). Remember: Only 'A' has an Antidote!

Anticoagulant Rodenticides

Mechanism of Action

Anticoagulant rodenticides inhibit vitamin K epoxide reductase (VKOR), the enzyme responsible for recycling vitamin K. This prevents the hepatic synthesis of vitamin K-dependent clotting factors II (prothrombin), VII, IX, and X. Factor VII has the shortest half-life and is depleted first, causing initial PT prolongation. Clinical bleeding occurs when factor II becomes deficient (typically 3-7 days post-ingestion).