Reversal of Vitamin-K Antagonists

1. Reversal of Vitamin-K Antagonists

2. Guidelines for Management for Nontherapeutic INR for patient on Warfarin Therapy Case AF อายุ 73 ปี INR 7.30 PT 68.20 -> No bleeding Off warfarin 2 วัน Vitamin K 2 mg PO

3. Vitamin K1 (Phytomenadione) 2 mg / 0.2 ml 10 mg / 1 ml

4. Oral route • Intravenous route • Subcutaneous route • Intramuscular route

5. Reversal of Vitamin-K Antagonists Pharmacokinetic of Vitamin K

6. IV • Do not use intravenously unless unavoidable. • Elevated INR with serious bleeding Hold warfarin therapy and give vitamin K1 (10 mg by slow intravenous (IV) infusion), supplemented with fresh plasma or prothrombin complex concentrate, depending on the urgency of the situation; recombinant factor VIIa may be considered as alternative to prothrombin complex concentrate; vitamin K1 can be repeated every 12 hrs. • Life-threatening bleeding Hold warfarin therapy and give prothrombin complex concentrate supplemented with vitamin K1 (10 mg by slow IV infusion); recombinant factor VIIa may be considered as alternative to prothrombin complex concentrate; repeat if necessary, depending on INR.

7. IV INTRAVENOUSRATE OF ADMINISTRATION If the intravenous route of administration is considered unavoidable, the drug should not exceed an administrative rate of 1 milligram/minute.

8. When vitamin K1 is administered to lower INRs, it should be administered at a dose that will lower the INR into a safe range quickly, without it being subtherapeutic, causing warfarin resistance, or exposing the patient to anaphylaxis risk. Low doses and slow infusion rates of vitamin K are recommended. If continuing warfarin therapy is indicated after high doses of vitamin K1, then heparin or low molecular weight heparin can be given until the effects of vitamin K1 have been reversed and the patient becomes responsive to warfarin therapy.

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