Online Coumadin Dosing Calculator
http://www.pace-med-apps.com/CoumCalc.htm
https://www.careinternet.net/caregiver/warfarin.php
Warfarin Sodium¹: Monitoring and Dosage Adjustment in Stable Anticoagulated Patients (based on a starting dose of 4 mg/d)
| INR² | Action |
|---|---|
| >10.0 | Stop warfarin. Contact patient for examination. |
| 7.0-10.0 | Stop warfarin for 2 days; decrease weekly dosage by 25% or by 1 mg/d for next week (7 mg total); repeat PT³ in 1 week. |
| 4.5-7.0 | Decrease weekly dosage by 15% or by 1 mg/d for 5 days of next week (5 mg total); repeat PT in 1 week. |
| 3.0-4.5 | Decrease weekly dosage by 10% or by 1 mg/d for 3 days of next week (3 mg total); repeat PT in 1 week. |
| 2.0-3.0 | No change. |
| 1.5-2.0 | Increase weekly dosage by 10% or by 1 mg/d for 3 days of next week (3 mg total); repeat PT in 1 week. |
| <1.50 | Increase weekly dose by 15% or by 1 mg/d for 5 days of next week (5 mg total); repeat PT in 1 week. |
¹ - Coumadin®, 1mg tablet
² - INR: International Normalized Ratio = (x/y)z , where:
x = Prothrombin Time of sample (sec)
y = Mean Normal Prothrombin Time (sec)
z = [ ISI of Thromboplastin]
