Anticoagulants are one of the classes of medicines most frequently identified as causing preventable harm and admission to hospital. There are two main groups of oral anticoagulants:

• Vitamin K antagonists (VKAs), including warfarin
• Non-vitamin K antagonists (apixaban, dabigatran, edoxaban and rivaroxaban), known as NOACs or direct oral anticoagulants (DOACs).

The use of non-vitamin K antagonist oral anticoagulants in atrial fibrillation (a heart rhythm disorder) is increasing, although warfarin continues to be widely used.

There are several different indications for oral anticoagulant therapy, and it is important to know why patients have been prescribed anticoagulants in order to be able to deliver appropriate advice and support. The most common uses are in the treatment of deep vein thrombosis or pulmonary embolism, collectively known as venous thromboembolism (VTE), and the secondary treatment of stroke in atrial fibrillation (AF).