Wednesday October 12, 2005
Argatroban and INR
Please note that you do not follow regular INR level to monitor Coumadin while overlapping with Argtroban. You may have to perform Special Coagulation Study - Chromogenic Xa level. General recommendation is to overlap argatroban and coumadin for no less than 5 days after starting coumadin at 5 mg/day and on day 3-4, obtain a Chromogenic Xa level.
Chromogenic Xa level of 40% corresponds to an INR of 2
Chromogenic Xa level of 20% corresponds to an INR of 3
Chromogenic Xa should be therapeutic for 24 hours before discontinuing argatroban.
And if above study is not available in your lab, general rule of thumb is to have INR atleast above 4.
Recommended Readings: Click on link to go to reference.
1. Argatroban - Massachusetts General Hospital
2. The International Normalized Ratio during Concurrent Warfarin and Argatroban Anticoagulation -Clinical Chemistry. 1999;45:409-412