Antithrombotics: Anticoagulants Including NOACs

Abstract

Anticoagulants are a class of drugs that inhibit coagulation cascade and blood clotting. For many years, anticoagulants were widely used for the prevention of ischemic stroke and systemic thromboembolic events. Warfarin is the most commonly used anticoagulant inhibiting the synthesis of vitamin K-dependent clotting factors. Recently, a number of new oral anticoagulant were developed to overcome limitations of the conventional vitamin K antagonist. With increase of the aged population, the proportion of cardioembolic stroke consistently increased. Atrial fibrillation is a common cardiac arrhythmia and the most important cause of cardioembolic stroke. Proper anticoagulation dramatically reduces the thromboembolic events in patients at high risk for cardioembolic stroke. However, anticoagulation also increases the risk for bleeding complications compared to placebo or antiplatelet. Clinicians should consider both the benefits and risks from anticoagulation therapy. Therefore, anticoagulation is only recommended for patients with expected net clinical benefit, absolute reduction of thromboembolic risk, and low bleeding risk from anticoagulation. CHA₂DS₂-VASc and HAS-BLED scores are widely used risk stratification tool for thromboembolism and bleeding complication on oral anticoagulation, respectively. Here, we will discuss on commonly used anticoagulants, their antidote, indications which need anticoagulation, and specific clinical issues with anticoagulation.