Rat Poisoning In Dogs

Rat poisoning is toxicosis due to inhalation or ingestion of ‘Rodenticides’, commonly referred to as ‘rat poisons’. The common targets for rodenticides usage are household small rodents i.e. mice/rats, field mice, deer mice, gophers, squirrels, etc.

The most commonly used rodenticides that are toxic to dogs are: bromethalin, anticoagulant rodenticides, and cholecalciferol. However, almost all rat poisons are extremely dangerous to dogs and can lead to life-threatening conditions.

Bromethalin poisoning increases pressure in cerebral edema and CSF leading to neurologic signs, while anticoagulant rodenticides poisoning causes excessive bleeding by interfering with vitamin K1 recycling in the body.

Cholecalciferol increases calcium absorption in the GI tract and reduces renal excretion of calcium resulting in hypercalcemia which in turn leads to mineralization of organs, with the most susceptible being kidneys, resulting in renal failure. All these types of poisoning require immediate medical intervention, or else it would be deadly.

• Bromethalin

• Large doses (signs manifest within 10 hours)
• Extreme hyper-excitability
• Severe muscle tremors
• Hyperthermia
• Hindlimb hyperreflexia
• Focal or generalized seizures

• Lower doses (signs manifest 2-7 days)
• Paresis or paralysis
• Hind limb ataxia
• CNS depression

• Anticoagulant Rodenticides (signs manifest within 3-7 days)

• Nose bleeds/ coughing (which may produce blood)
• Increased respiratory rate
• Lack of appetite
• Bloody or dark tarry stools
• Vomiting
• Enlarged abdomen
• Pale or Bleeding gums
• Bruising

• Cholecalciferol (12-36 hours after ingestion)

• Polyuria / polydypsia
• Dehydration
• Vomiting
• Anorexia
• Hind limb paresis
• Hyperthermia
• Cardiac arrhythmia
• Fatigue

Cholecalciferol Poisoning

1. Provide anti-vomiting medication (antiemetics).

2. There is no known antidote to cholecalciferol poisoning. Provide supportive care.

• Intravenous fluids and electrolyte support.
• Gastroprotectants (sucralfate, misoprostol, antacids).
• Thermoregulatory support (warming).
• hypercalcemia - pamidronate, an injectable bisphosphonate.

Bromethalin Poisoning Bromethalin ingestion of< 0.49 mg/kg:

• < 4 hrs of exposure, emesis itself is enough.
• If > 4 hr have elapsed after ingestion or if emesis is not successful, activated charcoal single dose at 1–2 g/kg body wt can be administered.

Bromethalin dosage of 0.5 mg/kg –0.75 mg/kg:

• The first dose of activated charcoal at 1–2 g/kg body wt.
• A total of 3 doses of 0.5 -1 g/kg at 8-hr intervals can be administered.

Bromethalin dosage of >0.75 mg/kg:

• Every 8 hrs- Administration of six doses of activated charcoal for 48 hrs.
• Anti-seizure medication (e.g., drugs like potassium bromide, phenobarbital, Levetiracetam, Premidone, etc).

Anticoagulant Rodenticides

• Blood product transfusions (RBCs, platelets, fresh frozen plasma (FFP), etc).
• Vitamin K as an antidote (3–5 mg/kg/day, PO, for 3–4 wk).

When you suspect the dog had insecticide poisoning-

• Take the rodenticide label to the vet.
• If the vet clinic is far away, follow the label's specific first-aid instructions carefully (if there are any).
• Make sure the pet is breathing and is not further exposed to the rodenticide before you call for emergency assistance.
• Always have a source of clean water available.
• For inhalation exposure- get the pet to fresh air immediately.

• If you use any insect or rodent bait in your home, make sure they are in locations not accessible to pets or in secure bait stations.
• Clean up the spills immediately, always apply in small amounts, and spread evenly.
• Use the right Baits and right spot. Many pets also find food baits appetizing.
• To reduce the risk of accidental pet poisoning, use sticky traps instead of spraying to kill insects and use snap traps for mice instead of rodenticides.
• Outdoor baits for rodents, gophers, and snails as well as slug baits can be highly toxic to dogs.
• Use less toxic baits (such as iron phosphate, and ferric sodium EDTA).

There is no breed disposition.

However, the top Breeds accounting for the most calls to Pet Poison Helplines are:

Boxer, Beagle, Chihuahua, Dachshund, Golden Retriever, German Shepherd, Labrador Retriever, Yorkshire Terrier, Shih Tzu, Mixed Breed

1. Causes:

• Cholecalciferol Poisoning
• First signs within 12–24 hr after ingestion, serum phosphorus level rises first, followed by an increase in serum calcium levels in another 12–24 hrs.
• A baseline biochemistry profile will be performed to test the phosphorus and calcium levels (analysis of both the blood plasma and other body fluids).
• Bromethalin Poisoning
• Exposure to higher doses of bromethalin usually manifests signs within 24 hrs of ingestion.
• Bromethalin and its primary metabolite content desmobromethalin result in intra-myelin fluid accumulation as they inhibit the coupling between the electron transport and phosphorylation reactions. This leads to intra-myelin cerebral edema and demyelinating disorders.
• The net result of increased CSF pressure, and cerebral and spinal edema leads to neurologic dysfunction.

• Anticoagulant Rodenticides

• Poisonous ingredients include 2-isovaleryl-1,3-indandione, Brodifacoum, Chlorophacinone, Diphacinone, Warfarin, etc.
• Anticoagulant rodenticide poisoning inhibit causes excessive bleeding by interfering with vitamin K1 recycling ( by inhibiting vitamin K(1)-2,3 epoxide reductase) in the body.

2. Mortality:

Rat poisoning in dogs is fatal and the mortality rate is actually higher. Worldwide data is not available; however, country-wise data itself suggests rat poisoning causes high fatality in dogs.

3. Diagnosis:

• Complete blood count (CBC), blood chemistry profile
• Electrolyte panel
• Urinalysis
• Blood pressure, heart function tests
• Additional tests for kidney or liver

4. Prognosis:

Prognosis will depend on the ingested quantity, proper diagnosis, and the timing of treatment. Earlier the diagnosis, recovery is good.

Even large doses of poisoning in dogs can be treated successfully if they get to the veterinarian right away. Mild cases may cause deaths if the poisoning was not found out until the dog succumbs or the cause is unknown.

Whenever you notice below mentioned signs, contact your vet immediately.

• Frequent vomiting
• Uncontrolled diarrhea
• Vocalization/ Crying/whimpering

Accompanied by Hypersalivation (excessive drooling) and some may roll around their backs.

• Lean boiled meats
• Chicken baby food
• Plain steamed or baked white fish (whiting, pollock, cod, haddock, etc)
• Mashed potato (softened with fish poaching liquor)
• Skinless, minced chicken or turkey
• Scrambled eggs
• Fibre rich foods: Apples, pears, oatmeal, and other foods
• Rice, sweet potato, mashed banana

Whenever toxic exposure is suspected, immediate action is recommended. Early consultation and treatment can help prevent serious health effects.