A 64-year-old woman with acute heparin-induced thrombocytopenia needs anticoagulation during coronary angiography. Which parenteral anticoagulant directly inhibits thrombin (factor IIa) without requiring antithrombin?
- A Enoxaparin
- B Danaparoid
- C Bivalirudin ✓
- D Warfarin
Correct answer: C. Bivalirudin
Explanation
Bivalirudin is a synthetic 20-amino-acid peptide analogue of hirudin that binds and directly inhibits both circulating and clot-bound thrombin independently of antithrombin. It is approved for percutaneous coronary intervention and is safe in HIT because it shares no epitope with heparin. Enoxaparin and danaparoid act via antithrombin and carry cross-reactivity concerns in HIT, while warfarin is contraindicated acutely due to venous limb gangrene risk.
Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 13th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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