Rat Poison Ingestion

Exposure to rodenticides (i.e. rat bait---toxic substances that kill animals after ingestion) is one of the top concerns in small animal veterinary medicine. These compounds are readily available over the counter and are often sold in pastes, paraffin blocks, pellets, concentrations, and tracking powders. They are made to be palatable and as such virtually any animal will find them appealing. Exposure to the following chemicals is always an emergency.

1) ANTICOAGULANTS

T he most common rat baits are those that prevent the ability of blood to clot. Clinical signs generally show up within 24-36 hours of ingestion. These signs may include—bruising, bleeding from nose/gums, blood in the urine or red/brown discolored urine, dark tarry stools, distended abdomen, trouble breathing, weakness, pale gums, coughing or vomiting up blood. These signs may be indicative of other diseases as well, so exposure to rat bait in the history is an important first step in the diagnosis.

Names of these chemicals include warfarin, brodifacoum, bromadiolone, difenacoum, pindone, chlorphacinone, and diphacinone. Of these, the most common is brodifacoum, (D-Con®).

If exposure is identified before clinical signs begin, progression can be prevented by a combination of cleansing the GI tract with activated charcoal and cathartics and with the long term replacement of vitamin K. The newer generations of rat baits can affect clotting for up to thirty days, so it would be important to treat your pet for this duration.

Prognosis is generally good with aggressive care.

2) CHOLECALCIFEROL (VITAMIN D3)

This chemical causes elevated blood calcium resulting in heart failure, kidney failure, and tissue calcification. Clinical signs show up within 12-36 hours of exposure and initially include depression, anorexia, vomiting, increased thirst and urination, and diarrhea. As clinical signs progress, kidney and heart failure occur. Damage can be irreversible depending on the dose and as such these animals need to be seen as soon as possible to initiate treatment.

3) PHOSPHIDES OF ZINC, ALUMINUM OR CALCIUM

These compounds are usually brownish-red (calcium), gray to yellow (aluminum), or dark gray crystals (phosphide). They are often found in grain or sugar baits. Clinical signs show up 30 minutes to 4 hours post ingestion and include vomiting, depression, tremors, seizures, and other abnormal behavior. Eventually the animal may collapse and be unable to rise or may run about aimlessly. There are no specific antidotes and the prognosis depends on the dose ingested and how aggressively supportive care is administered.

4) BROMETHALIN

This compound is relatively uncommon but still commercially available. There are no antidotes, and once moderate to severe clinical signs are apparent, prognosis is poor. It is important that animals exposed to this chemical be seen as soon as possible. Signs of exposure may include—muscle tremors, fever, paddling, excitability, vomiting, depression, abnormal response to stimuli, paralysis and seizures.

5) STRYCHNINE

This chemical is often sold applied to peanuts, wheat, or pellets. These may be dyed yellow, green or red. Early signs of toxicity include muscle spasm, restlessness, and anxiousness, and may rapidly progress to seizures, and severe sensitivity to touch and light. Eventually the animal becomes very rigid and has constant seizure activity. Usually animals will maintain consciousness until death. There is no specific antidote. Prognosis is generally good if the animal is treated aggressively and promptly.

Definitive care for exposure to these and other rat bait chemicals not mentioned here can require days of hospitalization.

If you must use rat baits make sure they are well out of reach of even the most inquisitive dogs and cats. Remember your pet may seek these products out by smell and even go to great lengths to get to them. Be cautious to inspect new areas including vacation cabins, homes that have been unattended for some time, and fields for signs of these products before allowing your pets access.