Brodifacoum is a readily available, second-generation anticoagulant rodenticide (superwarfarin) that causes extended depletion of vitamin K1-dependent clotting factors. Brodifacoum ingestions are being reported with increasing frequency. For the first time, we compare plasma brodifacoum concentration to prothrombin levels over time in a case of brodifacoum poisoning. Brodifacoum was eliminated according to a two-compartment model, with an initial half-life of 0.75 days and a terminal half-life of 24.2 days. On admission, the brodifacoum level was 731 μg/L and the patient suffered severe urinary tract hemorrhage, requiring transfusion of blood products. Persistently increased prothrombin times necessitated treatment with phytonadione up to 80 mg/d for 4 months, until the brodifacoum level reached 10 μg/L. These data may help project the duration of phytonadione treatment required in future cases of brodifacoum poisoning. Superwarfarin exposure must be suspected in an otherwise unexplained vitamin K1-deficient coagulopathy.
(Arch Intern Med. 1993;153:1925-1928)