Anticoagulant & Rodenticide (Warfarin & Superwarfarin) Poisoning

Also known as Warfarin overdose · Superwarfarin · Long-acting anticoagulant rodenticide · Brodifacoum · Vitamin K antagonist · VKORC1 · Prothrombin complex concentrate

The vitamin-K-antagonist anticoagulant poisoning — the therapeutic warfarin (a half-life measured in days) and the superwarfarin (the long-acting anticoagulant rodenticide — the brodifacoum, the bromadiolone — persisting for weeks to months). The inhibition of the vitamin-K-epoxide reductase (the VKORC1) — the impaired the gamma-carboxylation of the factors II, VII, IX, X and the proteins C and S — the coagulopathy. The bleeding. The vitamin K (the phytomenadione), the 4-factor prothrombin-complex concentrate for the active bleeding, and the prolonged (the weeks-to-the-months) vitamin K for the superwarfarin.

medium14 referencesUpdated 13 Oct 202614 min readSource-verified · Oct 2026

Checked against its sources on 13 Oct 2026

Practise this topic

8 MCQs

The one-paragraph exam answer

The vitamin-K antagonists split into the therapeutic warfarin (manageable over days) and the superwarfarins — long-acting anticoagulant rodenticides such as brodifacoum — whose effects last weeks to months (a terminal brodifacoum half-life of 24.2 days in the index pharmacokinetic case; treatment courses averaged 168 days). Both inhibit vitamin-K-epoxide reductase (VKOR), so clotting-factor synthesis fails and coagulation assays run beyond measurable limits. For active bleeding, guidelines recommend 4-factor prothrombin complex concentrate in combination with intravenous vitamin K1 — the PCC reverses within minutes, the vitamin K sustains the synthesis the PCC cannot. No active bleeding: vitamin K alone. Superwarfarin: high-dose vitamin K for weeks to months (treatment courses averaged 168 days in the largest review), or relapse is inevitable.

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Meet the patient

A 41-year-old pest-control worker arrives with gross haematuria, epistaxis and a thigh haematoma. His INR is over 15, the aPTT is prolonged, the fibrinogen and platelets are normal, and he takes no warfarin. The question that owns the next hour is the one examiners love to spring: why is this patient anticoagulated, and how long will the antidote need to run? A normal platelet count and fibrinogen with an unmeasurable INR and a rodenticide history is superwarfarin — months of vitamin K, not days.^[1]^[11]

References14Show

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