Brodifacoum toxicosis in two horses.

Increased popularity during the past decade of brodifacoum, an anticoagulant rodenticide, has led to an increase in cases of accidental poisoning in nontarget species, including pets and farm animals. Pharmacokinetics of second-generation anticoagulant rodenticides such as brodifacoum are substantially different from those of first-generation anticoagulant rodenticides such as warfarin. This difference dramatically influences management of exposure in terms of duration and cost of treatment and may affect outcome. The National Poison Control Center reports that approximately 50 cases of brodifacoum exposure have occurred in horses between 1993 and 1997. To our knowledge, this report is the first complete clinical description of accidental ingestion of a potentially lethal dose of brodifacoum in horses. Early recognition of exposure to brodifacoum, subsequent treatment with adequate doses of vitamin K1, and sequential monitoring of clotting times and serum brodifacoum concentration permitted poisoning in these horses to be managed successfully.