Hematology Question 6 Instructor

Contrast and compare the anti-coagulants warfarin, LMWH and the new oral anti-coagulants rivaroxaban and dabigatran with respect to their metabolism, elimination, and reversibility.

* Please check with your transfusion director regarding specific protocols for reversal of novel anti-coagulants.

 Drug Half-Life Elimination (Hours/Days) Reversal
Warfarin 20 to 60 hours 5 days Vitamin K,
Prothrombin Complex Concentrates,
Frozen Plasma
Unfractionated Heparin 45 minutes 4 hours Protamine
LMWH 3-6 hours (renal function) 24 hours Protamine
Dabigatran 11-17 hours (renal function) 1 to 3 days Dialysis (variable results),
Center dependent* (i.e. PCCs, FEIBA)
Rivaroxaban 5-9 hours (renal function) 1 to 2 days 90% protein bound – cannot be dialyzed,
Center dependent* (i.e. PCCs, FEIBA)

Warfarin is a vitamin K antagonist, metabolized through the liver and can be reversed with vitamin K, prothrombin complex concentrates and frozen plasma.

LWMH inhibits factors Xa and IIa via accelerating the activity of ATIII. It is renally cleared and must be used with caution in patients with renal failure. Reversal can be obtained with protamine.

Rivaroxaban is an oral FXa inhibitor that is renally cleared and does not require coagulation monitoring. In cases of bleeding factor Xa levels can be used to monitor therapeutic levels. There are no approved antidotes for reversal and protocols for reversal are center dependent.

Dabigatran is an oral thrombin inhibitor that does not require coagulation monitoring. There is no reversible antidote and coagulation testing is typically not used to monitor PT/ PTT values. There are no antidotes for reversal but dialysis has been used with limited success.

Dentali F et al. Safety of prothrombin complex concentrates for rapid anticoagulation reversal of vitamin K antagonists. A meta-analysis. Thrombosis & Haemostasis. 106(3):429-38, 2011 Sep.

Lowen, P and Dahri, K. Risk of bleeding with oral anticoagulants: an updated systematic review and performance analysis of clinical prediction rules. Annals of Hematologi. 90(10): 1181-200, 2011 Oct.

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