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 K(1) 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 K(1) therapy ( congruent with 7 mg/kg per 24 hours divided every 6 hours) was effective in treating brodifacoum-induced coagulopathy. The concentration of vitamin K(1) required for normal coagulation in this case was less than the accepted value of 1 microg/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 K(1) therapy.
Bruno
G R
GR
Department of Emergency Medicine, State University of New York Health Science Center at Brooklyn, Brooklyn, NY, USA. grbruno510@msn.com
Howland
M A
MA
McMeeking
A
A
Hoffman
R S
RS
D015110:4-Hydroxycoumarins / Q000097:blood / Q000493:pharmacokinetics / Q000506:poisoning*; D000284:Administration, Oral; D062787:Drug Overdose; D005500:Follow-Up Studies; D006207:Half-Life; D006470:Hemorrhage / Q000139:chemically induced / Q000188:drug therapy; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D010949:Plasma; D012378:Rodenticides / Q000097:blood / Q000493:pharmacokinetics / Q000506:poisoning*; D013406:Suicide, Attempted; D014812:Vitamin K / Q000008:administration & dosage / Q000627:therapeutic use*
D015110:4-Hydroxycoumarins; D012378:Rodenticides; D014812:Vitamin K; C013418:bromfenacoum