How a 3 kg body processes even tiny amounts
A pea-sized portion seems insignificant until you consider your cat's small size relative to target rodents. Modern anticoagulant rodenticides contain super-concentrated formulas where 1 gram can kill a 1 kg animal. Your 3 kg cat ate enough to overwhelm their clotting system once the poison fully circulates - and because it's stored in the liver, the effects compound over time.
The poison doesn't cause immediate symptoms because it works indirectly - it depletes vitamin K, which the liver needs to produce clotting factors. Since existing clotting factors last 12-72 hours before degrading, signs appear only once levels drop critically low. This delayed action makes owners falsely assume the danger has passed.
The deceptive calm before bleeding starts
Days 1-2 often look completely normal - your cat may eat, play, and behave typically while internal damage silently progresses. The first subtle changes are decreased activity (from microbleeds causing fatigue) and mild weakness (from anemia developing). These are easy to miss until more dramatic signs like collapse occur.
Watch specifically for changes in routine - skipping jumps they normally make, sleeping more than usual, or losing interest in favorite toys. These behavioral shifts often precede overt physical symptoms. Check gums daily - they should be bubblegum pink; any pallor warrants immediate vet attention, even without other signs.
Why early intervention beats waiting for symptoms
By the time you see obvious trouble like nosebleeds or limping (from joint bleeds), your cat has likely lost 20-30% of their blood volume. At 3 kg, that's life-threatening. Starting vitamin K1 now preserves remaining clotting factors before severe depletion occurs. It's far easier to prevent hemorrhage than treat it.
Vets can run a prothrombin time (PT) test to detect clotting problems before symptoms arise. This involves a simple blood draw - if results show prolonged clotting times, they'll begin vitamin K therapy immediately. Waiting for visible signs means playing catch-up with a poison that's had days to embed itself in your cat's system.
Long-term monitoring for small cats
Even with prompt treatment, your cat needs careful observation for weeks. Anticoagulants persist in the liver and can cause relapse if vitamin K is discontinued too soon. Expect at least 4-6 weeks of oral medication, with periodic blood tests to verify clotting times normalize.
Limit activity during recovery - jumping or rough play could trigger bleeding in fragile tissues. Use low-sided litter boxes to avoid straining. Report any new bruising, swollen joints, or breathing changes immediately - these suggest treatment adjustments are needed. With vigilance, small cats can recover fully from small exposures.
The step-by-step response, from the first minute to the vet visit, is in our Anticoagulant Rodenticide Toxicity in Dogs and Cats emergency guide.