Brodifacoum (Warfarin: with a vengance)

Brodifacoum is warfarin's mean sibling: it is another vitamin K analogue. It's so potent and has such a long half-life (on the order of months!) that it's more of a poison than an anticoagulant. It's used for the expected things; as a rat poison, etc. Interestingly, despite its lavish toxicity, all warfarin-type compounds, including brodifacoum, have an antidote: vitamin K (in controlled doses).