INR "too high to be measured". Patient on warfarin for a-fib and presently asymptomatic with no active bleeding or other bleeding risk factors. Treatment?

Hold warfarin.

Vitamin K 5 - 10 mg PO.

Monitor INR closely.

If INR were 5 - 9 (measurable, but high), omit 1 - 2 doses and resume warfarin at lower dose; OR omit 1 dose and give 1 - 2 mg of vitamin K PO before resuming lower dose.


Source

Winshall, J. and Lederman, R.  Tarascon Internal Medicine and Critical Care Pocketbook. 4th ed.