Rodenticide poisoning is one of the most common poisonings in dogs and cats. It is especially dangerous because, with the most widely used products, symptoms do not appear right away. Your pet may seem perfectly fine for days.
How do anticoagulant rat poisons work?
The most common rat poisons are anticoagulants. They prevent the body from using vitamin K1, which it needs to produce blood clotting factors. As a result, the blood cannot clot, leading to bleeding, often internal.
First generation (e.g. warfarin): usually need to be eaten repeatedly to cause serious poisoning.
Second generation (e.g. brodifacoum, bromadiolone): much more potent. A single feeding can be fatal.
When do symptoms appear? Clotting factors are used up within 1–2 days, and signs of bleeding usually appear 3 to 7 days after ingestion.
Symptoms
Important: bleeding is not always visible. It often occurs inside the abdomen, chest, lungs or joints.
Other types of rat poison
Not all rat poisons are anticoagulants, and there is no antidote for the following:
Cholecalciferol (vitamin D3): causes acute kidney failure. Signs appear within 2–3 days: increased thirst and urination, weakness, loss of appetite, bad breath. Even a small amount can be fatal.
Bromethalin: causes brain swelling. Signs (wobbliness, tremors, seizures, paralysis) can appear anywhere from 2 to 36 hours later. Cats are more sensitive than dogs.
Zinc/aluminium phosphides: release a toxic gas in the stomach. Signs appear quickly: bloating, vomiting, abdominal pain, shock, seizures.
That is why it is critical to know exactly which product your pet has eaten.
What to do immediately
Treatment
If the poison was eaten recently (within a few hours), the vet may induce vomiting and give activated charcoal.
For anticoagulants, the antidote is vitamin K1. It is a prescription medication, and over-the-counter supplements are not enough. Treatment lasts weeks: for potent second-generation anticoagulants usually about 4 weeks (28–30 days). Around 48 hours after the last dose, a blood clotting test confirms whether further treatment is needed. Severe cases may require hospitalisation and a blood transfusion.
With prompt treatment, recovery is possible. If bleeding goes unrecognised and untreated, it can be fatal.
Prevention
Sources
Merck Veterinary Manual – Anticoagulant Rodenticide Poisoning in Animals
VCA Animal Hospitals – Anticoagulant Rodenticide Poisoning in Dogs
Pet Poison Helpline – Mouse and Rat Poison (Rodenticides)
Pet Poison Helpline – Vitamin K1 for Dogs
This article is for information only and does not replace an examination by a veterinarian.