Oral Anticoagulation

Oral anticoagulants are a type of drug that reduces the body’s ability to form clots in the blood.  This increases the time the blood takes to clot.

Although they are sometimes called blood thinners, they do not actually thin the blood.  Oral anticoagulation will not dissolve clots that have already formed, although it will help to stop an existing clot from getting larger.

 

Are there different types of anticoagulants?

The oral anticoagulant drugs fall into several classes. Warfarin has been used in stroke prevention for many decades, and continues to be a very useful drug for managing atrial fibrillation. Indeed, its complication rate is reducing with better control of anticoagulation and the increasing trend for patients to self-test or self-manage their treatment.

There are several newer oral anticoagulant drugs which are being progressively introduced in many countries across the world. Although the newer oral agents are hailed as a major advance in stroke prevention care, there remain some concerns. They work in different ways and modify different parts of the clotting cascade.

Drugs such as warfarin, phenindione and acenocoumoral inhibit the vitamin K activity and are therefore termed Vitamin K Antagonists (VKA). The other category of drugs is NOACs – new oral anticoagulant drugs. These are dabigatran, which is an inhibitor of thrombin, and the two Factor Xa inhibitors – rivaroxaban and apixaban.

 

Are there risks associated with oral anticoagulation?

Unfortunately these groups of anticoagulant drugs (the VKAs and the NOACs) remain at the top of the highest risk category for any drug group.  However, the benefit in terms of reducing stroke is demonstrably high.  The challenge over the next few years is:

  • how best to learn from the opportunities presented by these newer drugs
  • how to ensure that the risk profile is defined for each and every patient
  • to become more sophisticated at choosing the right drug for the patient
  • to develop better processes and communication, to minimise the side effects of these very important drugs.