Argatroban Monitoring aPTT — FRCA Final MCQ

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HardIntensive Care MedicineArgatroban Monitoring aPTTFRCA Final

A 55-year-old woman on ICU has a confirmed diagnosis of heparin-induced thrombocytopenia. She is commenced on argatroban. What monitoring parameter is used to titrate argatroban therapy?

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Correct answer: C — INR

Argatroban (direct thrombin inhibitor) is monitored using aPTT, targeting 1.5-3× baseline (typically 50-80 seconds). It is hepatically cleared, so dose reduction is needed in liver impairment. Argatroban also elevates the INR (because it inhibits thrombin in the INR assay), which complicates transition to warfarin – overlapping therapy requires careful interpretation. When transitioning to warfarin, argatroban should be stopped and INR rechecked 4-6 hours later to obtain a true warfarin-only INR. Anti-Xa is used for LMWH/fondaparinux monitoring. ACT is used for heparin during CPB.

Reference: BSH – 2012 – HIT management; NICE – 2015 – NG24