August 25, 2016 Veterinarian In Palm Beach Gardens

Anticoagulant Rodenticides

These rodenticides result in a coagulopathy, causing hemorrhage or spontaneous bleeding. They are readily absorbed through the gastrointestinal tract after ingestion, and bind to plasma proteins as well as concentrate in the liver.

There are two generations of products that can be found, and unfortunately the second generations which are used more commonly are more toxic.  Some examples include: 1st generation- warfarin, pindone; 2nd generation- brodifacoum, bromadiolone, diphacinone, chlorophacinone.  The toxic doses of these products vary from 20-50mg/kg to even as little as 0.25-2.5mg/kg depending on the compound. Dogs seem to be more sensitive than cats.


Anticoagulant Rodenticides

The toxicity is caused by reduced vitamin K1- dependent clotting factors that occur in circulation after exposure.  Vitamin K1 is required in the reduced form by the body in order to activate clotting factors II, VI, IX, and X. When an animal has been exposed to anticoagulant rodenticides, the pathway of reducing vitamin K1 is inhibited, which then prevents the above clotting factors from being replenished. Without these clotting factors, coagulopathy develops, allowing for spontaneous bleeding.

It can take 2-3 days for clinical signs (hemorrhage) to occur after ingesting the rat bait as the clotting factors are used up and unable to be replaced. The bleeding can occur anywhere: through the GI tract, in the abdominal cavity, in the thoracic cavity or within the lungs, in the joints, or in the urinary tract. Severe hemorrhage can cause anemia. Sudden death may occur, especially if the bleeding occurs in the thoracic cavity. Generally, you see other signs first such as coughing, difficulty breathing, increased respiratory rate, exercise intolerance, lethargy, pale mucous membranes, or joint swelling. The prognosis is fair-poor. If the patient survives 48 hours after the acute coagulopathy the prognosis greatly improves.

If the ingestion was recent than immediate emesis followed by activated charcoal will be performed, once clinical signs have developed detoxification is too late. Depending on where the bleeding is occurring, the fluid may need to be removed. Plasma or blood transfusions may be necessary, as well as starting supplemental vitamin K1 to allow clotting factors to be activated appropriately. Depending on which product was ingested, the vitamin K1 will need to be continued for several weeks.

This can be a very serious and life threatening toxicity. If you believe your pet may have been exposed please bring him or her to a veterinarian immediately.