Four Deadly Poisons Every Pet Owner Needs to Know About

Analysis by Dr. Karen Shaw Becker

rodenticide poisoning in pets

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  • In the U.S., more than 100 pet deaths caused by rodenticides are reported to the U.S. Environmental Protection Agency each year
  • Rodenticide pellets, blocks or grain-based products may be spread around residential homes, garages, barns, farms, parks and wildlife areas
  • Anticoagulant rodenticides decrease clotting factors resulting in uncontrolled bleeding
  • Cholecalciferol rodenticides cause weakness, lethargy, decreased appetite and bad breath, with acute kidney failure developing two to three days after ingestion
  • Bromethalin, another type of rodenticide, is neurotoxic and causes cerebral edema, or fluid buildup around the brain; tremors, lack of coordination, seizures, paralysis and death can occur
  • Zinc and aluminum phosphides cause phosphine gas to be released, which can cause stomach bloating, vomiting, abdominal pain, shock, seizures and liver damage
  • If you think your pet has ingested rodenticide, get emergency veterinary care immediately, giving them as much information as possible about the product ingested so the correct course of treatment can be given

Rodenticides are one of the most common poisonings among pets, with one pet poison control center in Italy saying they represented 27.6% of calls received.1

In the U.S., more than 100 pet deaths caused by rodenticides are reported to the U.S. Environmental Protection Agency (EPA) each year,2 and there are likely many more that go unreported. Rodenticides also made the ASPCA’s Top 10 Pet Toxins list of 2019, coming in at No. 7.

Rodenticide exposure cases increased that year, making up 6.8% of the Animal Poison Control Center’s caseload.3 Part of what makes rodenticides so dangerous is their small size, which are easily chewed up by dogs and cats, and their widespread usage. Rodenticide pellets, blocks or grain-based products may be spread around residential homes, garages, barns, farms, parks and wildlife areas.

While many of the products appear similar, they can contain very different active ingredients, which affect what type of treatment is needed. If your pet consumes rodenticide, keep the packaging or try to give an accurate description of what it looked like to help veterinarians identify what type it is.

Four Common Rodenticides to Watch Out For

Following are the four most common rodenticides that all pet owners should be aware of.4 It’s best to avoid using these products in your home or garden, as pets have a knack for finding them, even if you think you’ve placed them out of reach. Pets, not to mention wildlife, can also be poisoned if they ingest a rodent that has recently consumed the rodenticide.

1. Anticoagulants

These can be either short-acting (warfarin) or long-acting (brodifacoum and bromadiolone), and work by inhibiting vitamin K1 epoxide reductase, which decreases clotting factors resulting in uncontrolled bleeding.

Signs of internal bleeding include lethargy, coughing, difficulty breathing and pale gums. Vomiting, diarrhea, nosebleed, bruising, bloody urine and bleeding from the gums may also occur, although less commonly.

Anticoagulant rodenticides have been banned for residential use since 2011, but if your pet is exposed treatment requires oral vitamin K1 for a period of five to 30 days. While cats rarely suffer poisoning from anticoagulants, dogs can be very sensitive to them and can be poisoned by ingesting a very small amount.

2. Cholecalciferol (Vitamin D3) — According to the Pet Poison Helpline, “For dogs and cats, this is one of the most dangerous rodenticides on the market and is gaining in popularity primarily due to EPA restrictions on second-generation anticoagulant rodenticides.”5

Symptoms of poisoning include weakness, lethargy, decreased appetite and bad breath, with acute kidney failure developing two to three days after ingestion. While there is no specific antidote, some animals respond to aggressive treatment including IV fluids and medications to help decrease calcium concentration in the body.

3. Bromethalin — This rodenticide is neurotoxic and causes cerebral edema, or fluid buildup around the brain. Tremors, lack of coordination, seizures, paralysis and death can occur, with symptoms developing anywhere from two hours to four days after ingestion. Activated charcoal, IV fluids and medications are needed to help reduce brain swelling. Cats are especially sensitive to bromethalin rodenticides.

4. Zinc and Aluminum Phosphides — These poisons produce toxic gasses and are often used in mole and gopher baits, but can also be found in rat and mouse bait. When ingested, phosphine gas is released, which can cause stomach bloating, vomiting, abdominal pain, shock, seizures and liver damage.

Giving antacids right after ingestion may help reduce the amount of gas produced, but immediate veterinary care is needed to decontaminate the stomach. Veterinary personnel are also at risk from fumes that can be released during this process or even from a pet’s vomit.

Pet Poison Helpline noted, “The toxic dose is very small and nearly all patients ingesting this poison need to be examined by a veterinarian. If the pet vomits in the car while en route to the veterinary clinic, the windows should be opened to prevent inhalation of phosphine gas.”6

If you think your pet has ingested rodenticide, get emergency veterinary care immediately, giving them as much information as possible about the product ingested.

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Nontoxic Pest Control Solutions

If you have pets, placing rodenticides in or around your home is a risk not worth taking. Nonchemical options like glue traps and snap traps aren’t a good alternative, as they cause significant suffering to the animals. Instead, I recommend a live trap called the Havahart®, which is a humane trap that catches mice, rats or other rodents so you can remove them from your home without using toxins or poisoning your environment.

If you set out live traps, be sure to check them at least once a day. Mice should then be safely released, ideally to another indoor location, as according to the Humane Society of the United States, “House mice and rodents that have lived in buildings for their entire lives will have a slim chance of surviving outdoors. If possible, relocate mice to an outbuilding like a shed or garage.”7

If this sounds strange, consider that mice are deserving of compassion too, and while you certainly don’t want to invite them into your kitchen, they’ve been living alongside humans, with little consequence, for thousands of years.

To protect your pets from rodenticides they may encounter outside of your home, keep your pet on a leash when visiting unfamiliar locations and don’t let your pet consume wild rodents, which may be tainted with rodenticide poisons.