Rat Bait Poisoning

by Dr. Francesca Matthews 

Rodenticides can be fatal for our pets too
In this article we are talking about anti-coagulant rodenticides. These include the first generation anticoagulants such as coumarin (warfarin and fumarin) and indanedione (chlorophacinone, valone and pindone); and second generation anticoagulants such as brodifacoum and flocoumafen.



Even those of you that are avid keepers of pet rats and mice will probably have the same feeling about wild rats and mice as the majority of the population. 


They spread disease, damage property and native flora and fauna and are just a little bit scary! (We've all seen the clips of the rodent plagues in the grain growing areas in the USA and Australia ... that's enough to give anyone a cold chill up the spine!).




The action of these anticoagulant rodenticides is to prevent blood clotting by reducing the vitamin K dependent coagulation factors. They essentially thin the blood. Warfarin is used in controlled quantities in human medicine to prevent clotting or to help break down small clots in humans.  


 Image source wikimedia commons

Repeated exposure to first generation rodenticides is usually required to be fatal and there is also a growing resistance in the rodent population to these. The second generation anticoagulant rodenticides are 10 - 20 times more potent than first generation and are effective in first generation resistant rodents. This consequently also makes them more dangerous for our pets too.




This will depend on how early the pet is presented. If the pet has just ingested or is suspected of ingesting rodenticide, diagnosis may be based on the contents of the vomit.


If it is slightly later, clinical signs may start becoming evident. They are not the same in every animal, but all the signs relate to the pet essentially bleeding internally. These may include pale gums, difficulty breathing, lethargy, being off food, lots of little haemorrhages on the mucous membranes (for example, gums). They are called petechial haemorrhages and are like little red or purple pin pricks. Other signs may include blood in the vomit, faeces and/or urine, salivation and abdominal pain.


Blood tests to look at how quickly the blood is clotting usually give a definitive diagnosis in animals that are showing clinical signs.




Unlike some poisons like 1080, there is an antidote for anticoagulant rodenticides and that is Vitamin K. Vitamin K may be given as an injection and/or orally. Because of the long half life of these rodenticides, vitamin K supplementation is usually required for 1 month.


In severely affected animals, they made need a blood transfusion too.


Despite the fact that there is an antidote, not all animals survive. If diagnosis is very late, then the damage may be irreversible. The good news is though that in most cases, animals will survive. The earlier treatment is sought, the better the prognosis.


Important notes


If you suspect your pet has eaten rodenticide or a rodent poisoned by rodenticide, don't delay, take them to your veterinarian. If possible, take the box that the rodenticide came from or at least try to be able to tell the veterinarian the name of the product.


Avoid taking your pets to areas where rodenticides may have been used. Warning signs will be posted where they are used in public places.


Don't allow your pets to eat sick or dead animals.


If you are using rodenticides around your home or property, make sure the bait is unable to be accessed by your pets. Dogs and cats are most at risk.

The image to the left shows an example of the use of carboard tubing to contain the bait. This works provided your pet is not prone to chewing cardboard. We would suggest hiding the tubing too to be on the safe side.


If you have any concerns that your pet may have been exposed to rodenticide or any otehr poison call us immediately for advice.


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