Warfarin or aspirin: both or others?

In general, aspirin is indicated to prevent thrombosis in conditions associated with high shear rates (i.e., atherosclerosis) and warfarin is indicated to prevent thrombosis in conditions associated with stasis (i.e., atrial fibrillation). While aspirin and warfarin should generally not be used together, their combined use is beneficial in selected patients (e.g., some patients with mechanical valve prostheses). Aspirin in a dose of 75-150 mg per day is indicated to prevent vascular events in patients with ischaemic heart disease and also in patients at high risk of ischaemic heart disease. All patients with atrial fibrillation should be considered for oral anticoagulant therapy, with the decision for its use based on an assessment of the balance between the risk of thromboembolism and bleeding. The recommended therapeutic INR (international normalised ratio) range in non-valvular atrial fibrillation is 2.0-3.0. Warfarin is contraindicated in pregnancy, particularly during the first trimester; however, it may still need to be used in the second and third trimesters in patients with mechanical valve prostheses.