Successful reversal of anticoagulant effect of superwarfarin poisoning with recombinant activated factor VII.
The use of second-generation anticoagulants termed "superwarfarins" as rodenticides, although widespread, is poorly controlled. Products containing superwarfarin have been marketed in over-the-counter rodenticides and can be easily purchased. Poor control potentiates the risk of accidental or intentional poisoning, but clinicians may underestimate the incidence of superwarfarin toxicity. Therefore, when cases of unexplained acquired coagulopathy and selective deficiency of vitamin K-dependent clotting factors occur in patients in the absence of liver disease or inhibitors, physicians should consider the possibility of superwarfarin poisoning as a cause. According to our own experience, recombinant activated factor VII (NovoSeven; Novo Nordisk, Bagsvaerd, Denmark) appears to be a safe and effective therapy for acute bleeding caused by superwarfarin poisoning. Due to the extended half-life of the second-generation rodenticides, follow-up therapy with oral vitamin K1 should be of long-term duration.