Memory Joggers: Medication Information
Managing Warfarin in Patients with High INR
INR > therapeutic range but < 5.0, no significant bleeding, rapid reversal not indicated for reasons of surgical intervention
Decrease or omit the next dose; resume at a lower dose when INR approaches desired range. If INR is minimally above therapeutic range, dose reduction may not be necessary.
INR > 5.0 but < 9.0, no clinically significant bleeding
When there are no additional risk factors for bleeding, omit the next 1-2 doses, monitor INR more frequently, and resume at a lower dose when the INR is in therapeutic range. When there is an increased risk of bleeding, omit the next dose, and give vitamin K1 (1.0-2.5 mg po). Patients requiring more rapid reversal before urgent surgery or dental extraction: give vitamin K1 (2-4 mg po); if the INR remains high at 24 h: give an additional dose of 1-2 mg.
INR > 9.0, no significant bleeding
Give vitamin K1 (3-5 mg po); closely monitor the INR; if the INR is not substantially reduced in 24-48 h, the vitamin K1 dose can be repeated. Serious bleeding or major warfarin overdose (INR > 20.0) requiring rapid reversal of anticoagulant effect: give vitamin K1 (10 mg by slow IV infusion), with fresh frozen plasma transfusion or prothrombin complex concentrate; depending upon urgency, vitamin K1 injections may be needed q12h.
Life-threatening bleeding or serious warfarin overdose
Give prothrombin complex concentrate, with vitamin K1 (10 mg by slow IV infusion); repeat if necessary, depending on INR.
Continuing warfarin therapy indicated after high doses of vitamin K1
Give heparin, until the effects of vitamin K1 have been reversed and patient is responsive to warfarin.
Key: INR, International Normalized Ratio.
Source: Hirsh J, Dalen JE, Anderson DR, et al. Oral anticoagulants: mechanism of action, clinical effectiveness and optimal therapeutic
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