Anticoagulant Rodenticide Poisoning in Dogs

Categories: Dog Health Care
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Anticoagulant Rodenticide Poisoning in Dogs

Charles Hurty, DVM

Grove Veterinary Clinic

The use of rodenticide poisons increases quite a bit during the fall.  The cooler temperatures of the changing season send mice and rats looking for warmer temperatures indoors.  These rodents can pose quite a problem, as they damage homes and introduce potential diseases.  Many people will use toxic bait-style poisons to deal with these pests.  If they absolutely must be used, these toxins need to be utilized with extreme caution, as they are extremely poisonous to dogs and other pets.

The rodenticide baits are aromatic and flavored and are thus appealing to the animals that encounter them.  In particular, dogs seem to like the flavor of these commonly used rat and mice poisons.  Because the flavor is appealing to dogs, rodenticide poisoning is one of the most common accidental poisonings that we encounter and treat.  If these poisons are utilized, they need to be kept inaccessible to our pets, as they can easily result in death.

Many of the rodenticides contain powerful anticoagulants, or chemicals that prevent coagulation, or clotting, of blood.  They do this by blocking the synthesis of Vitamin K, which is essential to the formation of several clotting factors.  These factors are important for normal blood clotting.  When these Vitamin K-dependent factors are inhibited or prevented from forming, spontaneous and uncontrolled bleeding results.  It is this uncontrolled bleeding that causes the death of the animal that ingests the rodenticide poison.

When a dog consumes the anticoagulant rodenticide, there may not be any clinical signs of illness for several days.  As the poison is absorbed into the dog’s body, it will start to affect the clotting system.  As the dog’s clotting ability is diminished, clinical signs will start to become apparent.   Typically, a dog that has ingested this poison will start to become pale and weak from blood loss.  One may notice multiple bruises over a dog’s body or splotchy bruises on a dog’s oral mucosa or gums.  Signs of external bleeding can include bloody vomit or diarrhea or even bloody urine or bleeding from the nostrils/nose.  The bleeding could also be occurring internally in the chest cavity or into the abdomen.  One may note respiratory distress if there is extensive bleeding into the lungs.  A dog’s abdomen or belly may look swollen if the internal organs are bleeding.  In some cases, seizures and neurologic signs can occur if the bleeding process is happening in the central nervous system.   Untreated these are patients that can easily die from this type of poisoning.

If you suspect that your dog has had contact with rodenticide poisons, you need to contact your veterinarian immediately.  There are some interventions and medications that can be given to help your pet survive this poisoning.  Sometimes blood transfusions or administration of other blood products are required to get your pet through a critical stage of the resulting illness.  Time is of the essence when dealing with any poisoning situation.