Back to Basics: Anticoagulation & Reversal

Mon, 09/21/2020 - 5:24am

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ANTICOAGULATION & REVERSAL by Valeria Wu

Warfarin

Mechanism: inhibits vitamin K dependent factors in coagulation cascade

Measured by: PT-INR
Requires bridging given transient thrombogenicity and frequent monitoring for therapeutic range
Teratogenic

Reversal

INR
3.0 - 4.5	Skip dose(s), close monitoring, resume when therapeutic
4.5 - 10.0 without significant bleeding	Skip dose(s), close monitoring, resume when therapeutic 1-2 mg PO vit K
> 10.0 without significant bleeding	Skip dose(s), close monitoring, resume when therapeutic 2-2.5 mg PO vit K Repeat as necessary
ANY INR with life threatening/significant bleeding	5 - 10 mg IV vit K bolus 4-Factor PCC INR < 4: 24U/kg (max 5000 U) INR 4 - 6 : 35U/kg (max 3500 U) INR > 6: 50U/kg (max 2500 U) OR 50 U/kg 4F PCC OR 10-15 ml/kg FFP OR rFVIIIa 80 ug/kg Redose as needed

Direct thrombin inhibitors: ie Bivalirudin (angiomax) - IV, Dabigatran (pradaxa) - PO

Direct factor Xa inhibitors: ie rivaroxaban (xarelto), apixaban (eliquis)

Shorter half life than warfarin, does not require as frequent monitoring
Renally excreted

Reversal

PCC: 2000 units or a weight-based dose of 50 units/kg
TXA: 10 to 20 mg/kg as an intravenous bolus
Consider DDAVP, drug removal (charcoal, hemodialysis)

Reversal agents

Dabigatran

Idarucizumab (Praxbind): 5 g

Oral factor Xa inhibitors

Andexanet alfa (AndexXa) dose dependent on inhibitor levels

4-factor PCC : 2000U or 25-50U/kg

References

Schulman S, Gross PL, Ritchie B, et al. Prothrombin Complex Concentrate for Major Bleeding on Factor Xa Inhibitors: A Prospective Cohort Study. Thromb Haemost 2018; 118:842.

Smith JL. Anticoagulants, Antiplatelet Agents, and Fibrinolytics. In: Cydulka RK, Fitch MT, Joing SA, Wang VJ, Cline DM, Ma O. eds. Tintinalli's Emergency Medicine Manual, 8e. McGraw-Hill; Accessed August 03, 2020.