Table 62. Warfarin dose adjustments.

INR value	Dose adjustment
≤ 1.5	Increase weekly dose by 15%
1.51 – 1.99	Increase weekly dose by 10%
2 – 3*	Maintain dose
3.01 – 4.0	Reduce weekly dose by 15%
4.01 – 4.99	Suspend 1 dose and reduce weekly dose by 10%
5.0 – 8.99	Suspend warfarin until INR is 2 to 3 then start again with weekly dose reduced by 15%
≥ 9.00	Hospitalization, suspend warfarin for an average of 4 days, prescribe vitamin K at a dose of 1 to 2.5 mg orally, repeating 24 to 48 hours later if INR does not decrease to < 5.0, and restart anticoagulation once INR is close to target value (below 4)

^*Consider maintaining the weekly dose of warfarin with INR up to 3.5, provided that the medication has not been initiated recently, and perform new measurement in 1 to 2 weeks. In case of the therapeutic INR goal is between 2.5 and 3.5, dose adjustments should occur adding 0.5 to the above values, with the exception of INR ≥ 9.0. INR: international normalized ratio.