Why a pea-sized piece is critical for an 8-week-old kitten
At this age, your kitten's liver is still developing and can't process toxins as efficiently as an adult cat. Even a tiny amount of anticoagulant rodenticide disrupts vitamin K recycling, which is essential for blood clotting. Their small body size means the poison's effects are more concentrated compared to a full-grown animal.
Signs like lethargy or weakness may seem vague at first, but they can signal internal bleeding that isn't visible. Kittens deteriorate faster than adult cats, so waiting for symptoms to appear is dangerous — immediate vet care can administer vitamin K before bleeding starts.
The silent danger you won't see tonight
Unlike some poisons that cause vomiting or drooling right away, anticoagulant rodenticide works invisibly. Your kitten might act normal for the first 12-24 hours while the poison depletes their clotting factors. By the time you notice pale gums or labored breathing, they've already lost significant blood internally.
Emergency vets often see kittens who seemed fine until they suddenly collapsed. Blood tests can detect clotting problems before visible bleeding occurs, which is why acting now — not when symptoms appear — gives the best chance for a full recovery.
Why home monitoring isn't safe for this case
You might be tempted to watch for symptoms since the amount eaten was small, but clotting factor depletion isn't something you can assess at home. A kitten's normal playfulness could mask early weakness, and their rapid metabolism means the poison works faster than in adult cats.
Vitamin K injections must start before bleeding begins to be most effective. Your vet may also run a clotting test called PT/PTT to confirm exposure, as some baits don't show effects for days despite the poison actively working.
What to expect at the emergency vet
The vet will likely administer vitamin K1 (not K2 or K3, which don't work for this poisoning) by injection, then send you home with oral doses for 2-4 weeks. They might hospitalize your kitten if signs of bleeding are already present, providing blood transfusions or oxygen support if needed.
Bring the bait packaging if possible — identifying the specific anticoagulant helps tailor treatment. Even if your kitten seems perfectly normal now, this is one situation where 'better safe than sorry' could literally save their life.
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.