Anticoagulant rodenticides continue to be one the most common enquiries to VPIS, particularly in dogs.

A single ingestion of a small amount of anticoagulant rodenticide is usually not a problem, but it may be difficult to know if the animal has eaten any other bait.

  • The owner may be certain that they have placed the bait safely but rodents can move grains, packets or even blocks of bait.
  • In addition, the rodent problem may not be isolated to a single household and neighbours or the local council may also be using rodenticide which could be accessible to pets.

Asymptomatic animals

  • If necessary contact VPIS to determine if the dose taken is a potential risk and whether treatment is required.
  • If a potentially toxic dose has been ingested gut decontamination (emesis and activated charcoal, if appropriate) can be undertaken if ingestion was recent.
  • Then vitamin K1 therapy can be started for at least 21 days OR the prothrombin time (PT) can be measured at 48-72 hours after ingestion. Note that taking blood for PT measurement after vitamin K1 has been given is not helpful since it be interpreted. Once the results are obtained the decision on vitamin K1 therapy can be made:
  • If the PT is normal, no treatment is required.
  • If the PT is prolonged treat with vitamin K1 for at least 21 days and assess clotting parameters 48 hours after the last dose.
  • If there is any delay in obtaining results of PT measurement and there is concern about the risk of bleeding then vitamin K1 therapy could be started once a blood sample is taken until the results have been obtained.
  • It is essential to prevent further exposure to anticoagulant rodenticides.

In animals NOT receiving vitamin K1 owners should be advised to look for any evidence of bleeding over the next few days e.g. cough, bleeding from gums or nose, blood in the stools, bruising, pale mucous membranes, lethargy or weakness, and advised to return immediately if their pet becomes unwell.

If there is any doubt about the amount ingested or there is the possibility of multiple episodes of ingestion – TREAT with the full 21 day course of vitamin K1.

Symptomatic animals

  • Any animal with evidence of bleeding should be admitted and started on vitamin K1 immediately and continued for at least 21 days.
  • The effect of vitamin K1 is not immediate so in an emergency a blood transfusion will be required. Clotting factors can be rapidly restored with one or more transfusions of plasma or whole blood.
  • Handle any animal with suspected bleeding with care.

Lola developed pulmonary haemorrhage after ingestion of rat bait. Read her story.