Don’t Eat That!
All Rodenticides are Not Created Equal!
The worst toxins are those that are made desirable for animals. Case in point, Rodenticide! Rodenticide is made to attract creatures! It is made to encourage an animal to eat and keep eating. Unfortunately, there are three main classes of rodenticide, and each has a totally different mechanism of action.
Types of Rodenticide:
1) Anti-coagulant Rodenticides- (Warfarin, Bromadiolone, and Brodifacoum)
This used to be the most common class of rodenticide. However, rodents began developing resistance to anti-coagulant rodenticides, so new classes were developed. In addition, EPA regulations have caused this rodenticide to be made unavailable to private consumers. Anti-coagulant rodenticides work by depleting vitamin K. Vitamin K is an important part of the process by which the body forms clots. When the clotting pathway is impaired, spontaneous bleeding can occur. This bleeding can occur anywhere in the body, and can be lethal. Bad as this one is, it’s actually the “best” one in that it is easiest to treat and has an antidote. Anti-coatulant rodenticide is no longer readily available to private consumers, but is the most common ingredient in older brands, as well as commercially used brands of rodenticides (including D-con and Tom Cat)
Clinical signs- pale mucous membranes, weakness, lethargy, collapsing, coughing, vomiting blood, dark bloody diarrhea, bruising, petechia (pin point bruising), distended abdomen, excessive bleeding from the gums.
Treatment- if the toxin was consumed within an appropriate time frame, decontamination can be performed. The treatment for all anti-coagulant rodenticides is oral vitamin K supplementation. Patients that are already showing clinical signs of bleeding may need a blood transfusion or a plasma transfusion and symptomatic care. These patients need supplementation with Vitamin K for as long as 30 days.
This type of rodenticide toxicity is increasing in frequency, as this is the most common type of rodenticide available to private consumers. Bromethalin depletes ATP, which is needed for the central nervous system to function properly. It leads to an accumulation of sodium and an influx of water into the central nervous system. Bromethalin leads to increased intracranial pressure and death. Unlike anti-coagulant rodenticides, there is no antidote. Tom Cat brands use bromethalin.
Clinical signs- Tremors, seizures, ataxia, loss of vocalization, loss of consciousness, paresis, paralysis, and death. Patients with mild signs may recover, but signs can last up to 2 weeks. Patients exhibiting severe signs usually do not recover.
Treatment- aggressive decontamination. Yes this does mean inducing vomiting, but it also means repeated doses of activated charcoal (which binds the toxin and prevents it from being absorbed.) Bromethalin undergoes enteroheptatic recirculation, which just means that it will be absorbed and re-enter the GI tract for an extended period of time. Repeated use of activated charcoal can alter the body’s electrolytes, so monitoring the patient’s bloodwork during treatment is also needed. Supportive care for the neurologic signs and increased intracranial pressure is needed for patients exhibiting these clinical signs. This includes manitol and medications to control tremors and seizures. Those patients who are exhibiting seizures, paralysis, and loss of consciousness are unlikely to recover, even with aggressive therapy.
3) Cholecalciferol-based rodenticides- Vitamin D3
Cholecalciferol (vitamin D3) causes increased absorption of Calcium from the GI tract. This leads to hypercalcemia (or increased calcium in the blood stream). Hypercalcemia results in kidney failure, tissue mineralization, and changes in heart function. One of the most challenging parts of this rodenticide is the delay in onset of clinical signs. Patients who have consumed Cholecalciferol often don’t show clinical signs for 18-36 hours. D-con brands use cholecalciferol most commonly.
Clinical signs- Vomiting, diarrhea, inappetence, lethargy, depression, increased thirst and urination, and cardiac arrhythmias (which may result in collapse, passing out, or death). Most commonly the deposits of calcium in the kidneys results in kidney failure.
Treatment- decontamination is usually initiated, however, Cholecalciferol is absorbed from the GI tract quickly enough that hypercalcemia is usually present even with quick and effective decontamination. Treatment for hypercalcemia involves frequent monitoring of the kidneys and calcium levels, fluid diuresis, and steps to remove calcium from the bloodstream. Treatment may be needed for several weeks, especially if the patient develops clinical signs. Severe signs result in a poor prognosis.
What can you do?
1) Prevent exposure. Even enclosed baits are not safe. Dogs can chew on the bait enclosures, resulting in exposure even in “child and pet safe” products. When moving to a new home, check all areas for rat baits. This is especially common in homes that have been vacant for a long period of time, or rental homes with basements or crawl spaces. When visiting family, confirm with the homeowner that no rodenticides are in use– this is especially common in rural areas with out-buildings, barns, and sheds. If you must use a rodenticide, make sure it is behind closed doors from your pets, and that all family members know the rat bait is in use. Supervise dogs in unfamiliar areas.
2) If you find your pet has consumed or had exposure to rodenticide, grab the label on the product and call animal poison control (888-426-4435). Head for your local veterinarian to induce vomiting. In most cases, having vomiting induced by your veterinarian is most effective. If you have a long drive, or delayed access to your veterinarian, call them and they can advise you on inducing vomiting before you head into the vet clinic. Poison control can also advise you on inducing vomiting. The recommendation to visit your veterinarian will always follow a recommendation to induce vomiting.
3) I’ll reiterate– grab the label! All brands of rodenticide make products with each of these different ingredients! Just knowing the brand is NOT enough to know the active ingredient or the strength of the product. Poison Control can easily look up the product from the data base if you have the label available, this is integral in quick and effective treatment.
Be calm. Quick treatment is life saving. Stopping the pet from consuming any more, and quickly initiating treatment is the best way to help your pet! Accidents happen. Act calmly and rationally and get your pet to a veterinarian to begin treatment!
Let’s celebrate Pet Poison Prevention Month together by learning about risks to our pets! We don’t need to look around every corner with fear! We just need to be aware of the risks to our animals and do our best to create a safe environment and to react appropriately when an accident does happen!