Deep Vein Thrombosis 환자에서 Warfarin 초기용량 5 mg/10 mg의 적절성 평가

Abstract

BACKGROUND : Treatment of DVT consists of unfractionated or low-molecular-weight heparin for 5 to 7 days, together with oral anticoagulation with warfarin given for minimum 3 months. It takes several days from starting warfarin to reaching a therapeutic level. A therapeutic level means that the blood is anticoagulated enough to treat the thromboembolism, but not too much. Too much warfarin can lead to bleeding complications. So it needs to establish correct warfarin starting dose. But the correct warfarin starting dose is not definitely established in Korea. METHOD : We retrospectively examined the charts of 49 DVT (Initial dose 5 mg : 14 patient, 10 mg : 35 patients) patients to evaluate the appropriateness of warfarin starting dose 5 mg, 10 mg by 4 criteria. The criteria is time to reach target INR 2.0~3.0, side effect occurring rate, times of maintaining each INR range, dose changing frequency. RESULTS : There were no differences in time to reach target INR 2.0~3.0 between 2 group (10 mg vs 5 mg : 4.69 ± 1.76 vs 5.50 ± 1.9 day (P=0.166)). But side effect occurring rate (4% vs 0% (P=0.001)), times of maintaining INR greater than 2.0 (P 0.05), frequency of decreasing dose (P=0.001) were higher in 10 mg starting group. Times of maintaining INR less than 2.0 was higher in 5 mg starting dose (P=0.021). CONCLUSION : Considering the time to reach target INR 2.0~3.0, it seems to be appropriate to start warfarin dose both 5 mg & 10 mg. But there were some differences in baseline characteristics between 2 groups (baseline INR value, number of patients showing PLT 150K, body weight). So it needs reinforcing prospective study controlling patient-baseline characteristics.