Reducing the risk of thromboembolic events

Warfarin is the most commonly prescribed anticoagulant in the UK and is used for both the treatment of thromboembolism (deep vein thrombosis, pulmonary embolism) and for thromboprophylaxis (atrial fibrillation, mechanical prosthetic valves or thrombophilia). It acts as a vitamin K antagonist, resulting in the formation of inactive forms of factors II, VII, IX and X; important steps in the clotting cascade. The evidence base supporting the clinical use of warfarin is extensive but it is far from an ideal treatment. There is a critical balance between thromboembolism prevention and haemorrhagic events. In addition, warfarin is susceptible to a wide range of drug interactions, due to its metabolism by cytochrome-P450, and has large interpatient dose variation. It is essential that regular monitoring and blood tests are performed and the patient receives sufficient education on warfarin treatment.