Effects of Diuretics on Warfarin Responses in Patients with Atrial Fibrillation

심방세동 환자에서 Warfarin 반응성에 이뇨제가 미치는 영향

  • Park, Hee Joo (Graduate School of Clinical Health Sciences, Ewha Womans University) ;
  • La, Hyen-Oh (Department of Pharmacy, Seoul St. Mary's Hospital, The Catholic University of Korea) ;
  • Gwak, Hye Sun (Graduate School of Clinical Health Sciences, Ewha Womans University)
  • 박희주 (이화여자대학교 임상보건과학대학원) ;
  • 나현오 (가톨릭대학교 서울성모병원 약제부) ;
  • 곽혜선 (이화여자대학교 임상보건과학대학원)
  • Received : 2012.12.12
  • Accepted : 2013.06.12
  • Published : 2013.06.30

Abstract

Purpose: Warfarin is the most widely used anticoagulant drug for preventing cardiovascular diseases after ischemic stroke and thromboembolism related to atrial fibrillation, artificial heart valves, deep vein thrombosis, and pulmonary embolism. Warfarin is commonly used in combination with other drugs such as diuretics in order to treat the comorbidity. Although several warfarin-diuretics interactions have been reported, the results are conflicting. Therefore, the initial aim of this study was to identify the effects of diuretics on the warfarin response in patients with atrial fibrillation. Methods: One hundred forty six patients with atrial fibrillation who were on anticoagulation therapy with warfarin and maintained INR levels of 2-3 for three consecutive times were followed up, retrospectively. Stable warfarin doses and INR per stable warfarin dose were compared according to age, gender, comorbidity, and concurrent medication. The stable warfarin dose was defined as the maintenance dose of warfarin of the measured patient whose INR was within the target INR range more than 3 times consecutively. Results: The differences of stable warfarin doses in patients with ($3.22{\pm}1.21$ mg/day) and without ($3.58{\pm}1.14$ mg/day) diuretics were marginally significant (P=0.069). On the other hand, stable warfarin doses were $2.97{\pm}1.10$ mg/day in patients with thiazide (n=36) and $3.58{\pm}1.14$ mg/day in patients without diuretics (n=82), which was statistically significant (p=0.009). INR values per stable warfarin dose in patients with diuretics and thiazide were $0.84{\pm}0.31$ and $0.90{\pm}0.34$, respectively, which were statistically different from those without diuretics ($0.72{\pm}0.21$, P=0.010 and P=0.006, respectively). Age, gender, and concurrent use of thiazide diuretics were found to have significant influence on the warfarin response from multivariate analysis. Conclusion: Our study showed that the concurrent use of thiazide diuretics could increase the response of warfarin in patient with atrial fibrillation. Therefore, clinicians should be aware that warfarin dose needs to be adjusted when it is used with thiazide diuretics concomitantly.

Keywords

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