For more information around the Traffic Light Covid Protection Framework, please CLICK HERE

Return to article List

Poisonings - Preventable Tragedies
Mill Road Vet Hospital / Tuesday, 27 June 2017

Poisonings - Preventable Tragedies


These generally contain Warfarin or related compounds, which act as anti - coagulants. They stop the blood clotting mechanisms in the rat that eats the poison, but unfortunately they have the same effect on pets, particularly dogs, who are just as likely to eat any bait they find.



  • Signs of poisoning do not show up until several days after eating the poison.

  • External bleeding is possible, but not common.

  • Internal bleeding is the usual symptom, but is often not evident. Signs include bloody or very dark stools, bloody urine or coughing up blood.

  • The most common symptom is weakness caused by loss of blood internally. Pale gums are also seen.



  • An in - house “PCV” blood test will quickly establish whether and to what extent the dog has become anaemic.

  • A “prothombin time” blood test at the pathology lab in Auckland will establish whether the blood loss is due to prolonged clotting time.



  • If the dog has just been seen to have eaten rat bait we can make the dog vomit.

  • Vitamin K1 is the antidote to warfarin type poisonings. We start treatment with an injection and send the dog home with a two week course of tablets. The different classes of anticoagulants vary in how long they stay in the body, so we re - test prothrombin time two days after finishing treatment, and often have to continue treating for several more weeks.

  • The cost of diagnosing and treating a 25kg Labrador for two weeks is typically about $300.

  • Blood transfusion! Often by the time a poisoned dog arrives at the clinic it has lost so much blood the only thing that will save it is a blood transfusion. We have to call up a donor dog, collect blood and transfuse before we lose them. They need hospitalization for some time and will go home with a bill of $1200 or more.


Secondary poisoning by eating a poisoned rat is possible in theory, but in practice we hardly see it, but what does catch peo ple out is that rats will move baits. They carry them back to their nests and can drop them on the way.

The take home message: Take extreme care when using rat bait. Watch out for dropped baits and check your dog every day while you’re poisoning: Look for pink gums and plenty of energy. If in doubt; get him checked!



Most slug bait sold in garden centres contains Metaldehyde. Again, dogs are the most commonly poisoned pets, because they are not fussy about what they eat. (Slug bait is often advertised as having “pet deterrents” added, but nobody told the dogs! They like this stuff and they don’t need much).


  • Metaldehyde is a neurotoxin. Signs develop fairly quickly after eating the slug bait. They start with twitching, which quickl y progresses to uncontrollable seizures, respiratory failure and ultimately death.



  • The appearance of the twitching patient is usually quite characteristic.



  • There is no antidote for metaldehye. If the patient’s symptoms have not progressed too far we make them vomit and give them activated charcoal to bind the toxin and prevent further absorption. Tremors are controlled with sedatives.

  • More advanced cases need full anaesthesia and their stomachs pumped. Depending on how much toxin has been absorbed these dogs may need to be kept anesthetized for several days. This obviously requires intensive hospitalization day and night and these cases will go home, if we save them, with bills up to $1500!


The take home message: Don’t use this stuff!!! There is a product called “Quash” which is completely safe for pets and very effective at killing slugs and snails. Tell your neighbours', tell everyone!!

Return to article List

Theme picker