A randomized trial comparing 5-mg and 10-mg warfarin loading doses.

Abstract
ALTHOUGH WARFARIN sodium is an effective antithrombotic agent, it has a narrow therapeutic window and a widely variable dose-response relationship among patients with thromboembolic disorders. An inadequate anticoagulant effect is associated with reduced efficacy,1 and an excessive anticoagulant effect with increased bleeding.2 Consequently, the anticoagulant effect of warfarin has to be monitored carefully and the dose adjusted so that the prothrombin time (PT) is maintained in a safe and effective range. For most thromboembolic disorders, the therapeutic range for the PT is equivalent to an international normalized ratio (INR) of 2.0 to 3.0.3