Diphenadione is a vitamin K antagonist which has anticoagulant effects and is used as a rodenticide against rats, mice, voles, ground squirrels and other rodents. This chemical compound is an anti-coagulant with longer activity than warfarin and other synthetic indandione anticoagulants. Diphenadione is highly toxic for human skin by all means of contact. Consumption of the drug may cause major blood clotting and irregular heartbeats. An online pesticide database gives more information about the safety of diphenadione. The U.S. Environmental Protection Agency has issued a safety handbook which explains how incidents of poisoning with similar rodenticides are usually treated. For treatment purposes Vitamin K antagonists like diphenadione are placed under the heading of coumarins and indandiones.