A patient on dabigatran presents with life-threatening intracranial haemorrhage. Idarucizumab is administered. Its reversal mechanism involves:

• A Recombinant modified human factor Xa decoy protein that competes with dabigatran for fibrinogen binding
• B Activated charcoal that binds dabigatran in the GI tract and reduces systemic exposure
• C Humanised monoclonal antibody fragment (Fab) that binds dabigatran with 350 times greater affinity than dabigatran's own affinity for thrombin, sequestering both free and thrombin-bound dabigatran and restoring thrombin activity within minutes ✓
• D Vitamin K analogue that restores prothrombin synthesis, bypassing dabigatran's thrombin inhibition

Explanation

Idarucizumab (Praxbind) is a humanised monoclonal antibody fragment (Fab) specifically designed as a structural analogue of dabigatran's thrombin-binding interface. It binds dabigatran with subpicomolar affinity — approximately 350-fold higher than dabigatran's affinity for thrombin — rapidly sequestering both free plasma dabigatran and dabigatran-thrombin complexes. The REVERSE-AD trial showed complete reversal of dabigatran anticoagulant effect within minutes of infusion. Andexanet alfa is the reversal agent for factor Xa inhibitors (rivaroxaban, apixaban, edoxaban). Activated charcoal is only useful if dabigatran was ingested within 2 hours.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.