Charlie -  Rodenticide Anticoagulant Toxicity

By Brent Megarry, DVM

An 8 month old male lab puppy was presented to our clinic complaining of lethargy and not eating.  The 60 pound puppy actually collapsed while being unloaded from the owner’s car.  On presentation the dog had pale mucous membranes and a rapid heart rate.  Initial blood work showed the coagulation factors to not only be high but off the scale.  The puppy was also very anemic with low total solids in his plasma.  The treatment was started not only quickly but aggressively.  The dog was immediately placed into oxygen and blood typed.  Aggressive Fresh frozen Plasma, FFP, therapy was initiated and administered at a very high rate.  The dog tried to expire during treatment three times.  By the end of the FFP transfusion, approximately 2 hours, the dog’s blood pressure was much improved and the dog was becoming more alert and playful.  Radiographs indicated that the dog had bled a large volume in the space between the lungs and the chest wall causing respiratory difficulty along with pronounced low blood pressure.  The FFP transfusion contains the coagulation proteins the rodenticide had inactivated.  As the coagulation factors were given via the FFP, the dog was again able to control bleeding.  In fact, the non-coagulated blood located in the dog’s chest was actually reabsorbed into the puppy via his lymphatic system.  The administration of Vitamin K to the dog was also started to overcome the toxicity of the rodenticide ingested.  After approximately 48 hours of intensive care the lab puppy was able to rejoin his family.  The dog was kept on supplemental Vitamin K for 3 weeks and will return for a recheck after the three week treatment period.

Vitamin K dependent rodenticides inactivate the vitamin K normally found in the animal’s body.  Animals get vitamin K from the diet they eat.  Without unaltered vitamin K, the coagulation system will not function.  By giving this puppy vitamin K and the coagulation proteins found in FFP, the dog immediately stopped bleeding.  The oral supplemental Vitamin K therapy given over a three week period is crucial.  It will take two to three weeks for the dog’s body to clear the rodenticide eaten.  The dog could have never eaten enough rodenticide to inactivate the amount of oral vitamin K the dog is to be administered.  Therefore by the time the three weeks of therapy is over, no more rodenticide is found in the dog’s body. 

Animals don’t just have to eat the rodenticide directly but can also become poisoned from eating the animals that have consumed the mouse bait.  It is very important to use extreme caution when using rodenticides.  Accidental exposures to pets happen far too frequently.  Some animals are not as lucky as the young dog described above.

Brent Megarry, DVM
Dr. Megarry is a native of Minnesota.  He attended the University of Arizona and the University of Minnesota College of Biological Sciences graduating Magna Cum Laude in 1987.  He earned his Doctor of Veterinary Medicine degree from the University of Minnesota College of Veterinary Medicine in 1991.  He practiced small animal, equine, surgery, and production medicine until the year 2000 when he dedicated himself exclusively to small animal emergency medicine and surgery.  In 2002, Dr. Megarry joined Veterinary Emergency & Specialty Centers in Albuquerque as an emergency veterinarian. When not practicing veterinary medicine, Dr. Megarry can be found riding his horses, traveling, or skiing.