MJA Practice Essentials - 10. Warfarin or aspirin: both or others?

In general, aspirin is indicated to prevent thrombosis in conditions associ ated with high shear rates (ie, atherosclerosis) and warfarinis indicated t o prevent thrombosis in conditions associated with stasis (ie, arrial fibri llation). While aspirin and warfarin should generally not be used together, their com bined use is beneficial in selected patients (eg, some patients with mechan ical valve prostheses). Aspirin in a dose of 75-150 mg per day is indicated to prevent vascular eve nts in patients with ischaemic heart disease and also in patients at high r isk of ischaemic heart disease. All patients with arterial fibrillation should be considered for oral antic oagulant therapy, with the decision for its use based on an assessment of t he balance between the risk of thromboembolism and bleeding. The recommended therapeutic INR (international normalised ratio) range in n on-valvular atrial fibrillation is 2.0-3.0. Warfarin is contraindicated in pregnancy, particularly during the first tri mester; however it may still need to be used in the second and third trimes ter in patients with mechanical valve prostheses.