Understanding anticoagulant and other rodenticide poisoning in cats — recognition and emergency management.
Anticoagulant rodenticide poisoning causes severe welfare impairment through internal haemorrhage that develops insidiously over days. By the time clinical signs appear — sudden lethargy, difficulty breathing from pleural haemorrhage, pale mucous membranes from anaemia — significant blood loss has already occurred. Cats may be found collapsed with no obvious cause by owners who are unaware of any rodenticide exposure.
The delayed onset is the most dangerous welfare feature. A cat that appears normal after rodenticide exposure may deteriorate dramatically 3-7 days later when anticoagulant effects become clinically apparent. Without prompt treatment, severe haemorrhage causes death from cardiovascular collapse, pleural haemothorax, or retroperitoneal bleeding.
Treatment with vitamin K1 (phytonadione) for a minimum of 4-6 weeks is required for second-generation anticoagulants — much longer than for first-generation compounds. Stopping treatment prematurely before the rodenticide is fully metabolised causes relapse. Blood transfusions provide immediate relief for severely anaemic cats while vitamin K takes effect.