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Warfarin Maintenance Dosing Adjustment Nomogram
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The authors make no claims of the accuracy of the information contained herein; and these suggested doses and/or guidelines are not a substitute for clinical judgment. Neither GlobalRPh Inc. nor any other party involved in the preparation of this document shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any user's use of or reliance upon this material.    PLEASE READ THE DISCLAIMER CAREFULLY BEFORE ACCESSING OR USING THIS SITE. BY ACCESSING OR USING THIS SITE, YOU AGREE TO BE BOUND BY THE TERMS AND CONDITIONS SET FORTH IN THE DISCLAIMER.
Warfarin Maintenance Dosing Adjustment Nomogram for INR Goal of 2-3
Adjustment Guidelines
  • A: Baseline CBC, PT/INR required prior to continuation of warfarin therapy.

  • B: Assess patient compliance and determine if any changes have been made that may impact therapy: 1) addition of interacting drugs or herbal products; 2) changes in diet (eating/not eating) 3) changes in health status.

  • C: Based on the INR results make adjustments to the current therapy based on the ranges below:
Adjustment Guidelines   Printable version
INR < 1.5
1. ] Verify compliance (if non-compliant: resume therapy at previous dose).
2. ] If dosage adjustment needed: increase maintenance dose by 5%- 20%*.

[* Some clinicians recommend a 'booster dose' 1.5 to 2x the daily maintenance dose x 1 ]
3. ] Return: 3 – 7 days
INR 1.5 - 1.9
1. ] Verify compliance (if non-compliant: resume therapy at previous dose).
2. ] [* Some clinicians recommend a 'booster dose' 1.5 to 2x the daily maintenance dose x 1 ]
3. ] If dosage adjustment needed: increase maintenance dose by 5 - 15% (use lower end of this range for INR values close to the therapeutic range).
4. ] Return: 3 – 7 days
INR 2.0 - 3.0
1. ] No Changes Needed
2. ] Return: 4 weeks
INR 3.1 - 3.4
1. ] Dose adjustment usually not necessary if level is at the low end of this range ( 3.1 – 3.2) and at least two previous levels were therapeutic. Recheck in 3 to 7 days.
2. ] Consider decreasing dose by 5 - 10% and/or holding one dose.
3. ] Recheck in 3- 7 days.
INR 3.5 - 3.9
1. ] consider holding one dose.
2. ] evaluate any clinical changes that may have occurred with the patient (eating regularly, no new medications, etc.)
3. ] consider decreasing the maintenance dose by 5 -15% depending on magnitude of the INR elevation.
4. ] Return: 1- 3 days.
INR 4.0 - 4.9 with no significant bleeding
1. ] Hold warfarin until INR is within the therapeutic range.
2. ] Recommend lowering maintenance dose by 5%- 20%
3. ] Increase frequency of monitoring until problem resolved (daily initially).
4. ]  (8th ACCP)1:  If only minimally above therapeutic range or associated with a transient causative factor, no dose reduction may be required.
INR > 5.0
1. ] See 8th ACCP guidelines.1
2. ] Return: daily

Warfarin related Links

References:

1. Ansell J, Hirsh J, Hylek E, Jacobson A, et al. Pharmacology and Management of the Vitamin K Antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. 2008 (suppl 6);133:160s-198s.

Disclaimer

All calculations must be confirmed before use. The authors make no claims of the accuracy of the information contained herein; and these suggested doses are not a substitute for clinical judgement. Neither GlobalRPh Inc. nor any other party involved in the preparation of this program shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any user's use of or reliance upon this material.PLEASE READ THE DISCLAIMER CAREFULLY BEFORE ACCESSING OR USING THIS SITE. BY ACCESSING OR USING THIS SITE, YOU AGREE TO BE BOUND BY THE TERMS AND CONDITIONS SET FORTH IN THE DISCLAIMER.   Read the disclaimer
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