The first prospective, randomized clinical trial comparing
warfarin initiation with 5 or 10 mg included 49 patients,
most of whom were being treated for venous thromboembolism.
7 All patients had target INRs of 2.0–3.0. Warfarin
doses were based on the protocol shown in Table 1.30 The
patients were randomly assigned to receive either 5 or 10
mg of warfarin on days 1 and 2 of the study. However, the
day-2 dose was reduced if the subject’s INR was >1.5.