Long-Acting Anticoagulant Overdose: Brodifacoum Kinetics and Optimal Vitamin K Dosing

Ingestion of long-acting anticoagulant rodenticides such as brodifacoum can lead to prolonged and life-threatening coagulopathy. A paucity of conflicting information is available on brodifacoum’s half-life and elimination pharmacokinetics. In addition, the optimal dose, duration, and route of administration of vitamin K1 therapy are unknown. We report the case of a 52-year-old man who ingested eight 43-g boxes of a rodenticide (d-Con Mouse-Prufe II; 0.005% brodifacoum; Reckitt & Colman, Wayne, NJ). This case demonstrates that after stabilization with fresh frozen plasma, high-dose oral vitamin K1 therapy (congruent with7 mg/kg per 24 hours divided every 6 hours) was effective in treating brodifacoum-induced coagulopathy. The concentration of vitamin K1 required for normal coagulation in this case was less than the accepted value of 1 μg/mL, which is derived from a rabbit model. In this case, brodifacoum appears to follow zero-order elimination pharmacokinetics. In future cases of patients with ingestions of long-acting anticoagulants who present with coagulopathy, it may be useful to obtain serial brodifacoum concentrations to determine elimination curves to help predict the duration of oral vitamin K1 therapy. [Bruno GR, Howland MA, McMeeking A, Hoffman RS. Long-acting anticoagulant overdose: brodifacoum kinetics and optimal vitamin K dosing. Ann Emerg Med. September 2000;36:262-267.]