Problem-Based Review: Non Vitamin K Antagonist Oral Anticoagulants for the Acute Physician

Non-vitamin K antagonist oral anticoagulants (NOACs), are direct anticoagulants which inhibit specific coagulation factors and function as anticoagulants. Three NOACs are currently licensed in the United Kingdom: dabigatran, a thrombin inhibitor, and rivaroxaban and apixaban, antagonists of factor Xa. They are set to change the anticoagulant landscape, which was previously ruled by warfarin and heparins. Their advantages including oral formulations, rapid onset and offset of action, predictable pharmacokinetics, no requirement for routine blood monitoring or dose adjustment and very few drug interactions. The increasing use of these drugs means the acute medicine physicians are likely to encounter patients who have been taking them. This article reviews some of the challenging clinical situations in which this may arise.