3DChem.com - Chemistry, Structures & 3D Molecules a visual and interactive website showcasing the beautiful world of chemistry

Warfarin (Molecule of the Month for July 2004)

Coumadin and Marevan

Warfarin is an anticoagulant medication that is administered orally. It is used for the prophylaxis of thrombosis and embolism in many disorders. Its activity has to be monitored by frequent blood testing for the international normalized ratio (INR). Warfarin was originally developed as a rat poison, and is still widely used as such, although warfarin-resistant rats are becoming more common.

Normally, vitamin K is converted to vitamin K epoxide in the liver. This epoxide is then reduced by the enzyme epoxide reductase. The reduced form of vitamin K epoxide is necessary for the synthesis of many coagulation factors. Warfarin inhibits the enzyme epoxide reductase in the liver, thereby inhibiting coagulation. Therapeutic drug monitoring is required, as warfarin has a very narrow therapeutic index, which means the levels in the blood that are effective are close to the levels that cause bleeding. Dosing of warfarin is further complicated by the fact that it is known to interact with many other medications and other chemicals which may be present in appreciable quantities in food (including caffeine and ascorbic acid). These interactions range from enhancing warfarin's anticoagulation effect to reducing the effect of warfarin.

Warfarin is used for controlling rats and mice in residential, industrial, and agricultural areas. It is both odorless and tasteless. It is effective when mixed with food bait, because the rodents will return to the bait and continue to feed over a period of days, until a lethal dose is accumulated (considered to be 1 mg/Kg/day over four to five days). It may also be mixed with talc and used as a tracking powder, which accumulates on the animal's skin and fur, and is subsequently consumed during grooming. The use as rat poison is now declining as many rat populations have developed resistance to warfarin.

Formal Chemical Name (IUPAC)



Picture of Warfarin 3D model

click on the picture of  Warfarin above to interact
with the 3D model of the
Warfarin structure
(this will open a new browser window)

Picture of Warfarin


Update by Karl Harrison
(Molecule of the Month for July 2004 )

Stacks Image 34 All the images on this web site are are made available with a Creative Commons Attribution license and so can be used as long as the attribution
© Karl Harrison 3DChem.com is written with the image. High resolution images and illustrations are available on request.