Indications for anticoagulant and antiplatelet combined therapy

#### What you need to know Antithrombotic medications reduce thromboembolic events by inhibiting platelet aggregation and coagulation. Antiplatelet drugs and oral anticoagulants are examples of antithrombotic medications and are among the most commonly prescribed drugs in both primary and secondary care.1 Clinicians are familiar with their use, however antiplatelets and oral anticoagulants are the drug classes most commonly implicated in adverse drug reactions occurring both in the community and in hospital.23 Increasing numbers of patients have an indication for combination antiplatelet and oral anticoagulant therapy. For example, more than one million people in the UK have atrial fibrillation, of whom approximately one third also have an indication for antiplatelet therapy as secondary prevention.4 Despite the need to understand the balance between benefit and risk, there are limited randomised data investigating antithrombotic co-prescription. Current guidelines are therefore based on expert opinion and the extrapolation of non-randomised data. Patients can develop independent indications for antiplatelet and oral anticoagulant therapy, but in most cases the pathophysiology will intersect. The relationship between cardiovascular disease and atrial fibrillation is the typical example, where one fifth of patients presenting with atrial fibrillation will subsequently require coronary intervention, and up to one fifth of acute coronary syndrome (including ST elevation myocardial infarction, non-ST elevation myocardial infarction, and unstable angina) presentations develop atrial …