Management overview for superwarfarin poisoning

Long-acting anticoagulant rodenticides (pesticides that kill rodents), known as ‘superwarfarins’, are a class of high-potency, very long-acting anticoagulant drugs. They include brodifacoum, bromadiolone, coumatetralyl, difenacoum difethialone, diphacinone, flocoumafen and pindone. Large ingestions can result in a delayed-onset anticoagulated state that can last for months.

Accidental exposures in children are rarely associated with adverse effects—young children seldom ingest enough to cause any problems as most rodenticides have a taste deterrent in them. In most cases, no investigation or treatment is required. Consider nonaccidental injury in any child who has evidence of bleeding or a raised international normalised ratio (INR) after exposure to these agents.

Phytomenadione (vitamin K₁) is an effective antidote for superwarfarin poisoning, but must not be administered until anticoagulation is confirmed by INR measurement. Phytomenadione (vitamin K₁) therapy may need to be continued for months.

For the management of patients with poisoning due to deliberate or accidental ingestion of warfarin, see here. For management of a raised international normalised ratio (INR) in patients taking warfarin therapeutically, see here.