These anticoagulants work by working against vitamin K in the liver. These anticoagulants are generally used to treat patients with deep vein thrombosis, pulmonary embolism, atrial fibrillation, and mechanical prosthetic heart valves.

The most commonly used example of a vitamin K antagonist is warfarin.

Another example available in Australia is phenindione (Dindevan^®). This medicine is not commonly used as there are a lot more side effects associated with its use, but it is sometimes a good choice for people who can't take warfarin.