Overview
Direct thrombin inhibitor for HIT, hepatically metabolized. Used when heparin contraindicated. Short half-hour allows quick titration. Monitored with aPTT.
Dosing
HIT: 2mcg/kg/min IV (no bolus) Adjust to aPTT 1.5-3x baseline Hepatic impairment: Child-Pugh A: 0.5mcg/kg/min Child-Pugh B/C: Avoid Max dose: 10mcg/kg/min
Pharmacokinetics
Onset: Immediate Peak: Steady state in 1-3hr Duration: 2-4hr Metabolism: Hepatic Elimination: Fecal Half-life: 45min
Pharmacodynamics
Mechanism: Direct reversible thrombin inhibition Effects: - Binds free and clot-bound thrombin - No cross-reactivity with HIT antibodies - Increases PT/INR (affects warfarin transition) - No antidote
Clinical Considerations
Clinical Pearls: 1. First-line for HIT with thrombosis 2. No bolus required 3. Monitor aPTT q4hr until stable 4. Overlap with warfarin until INR >4 5. No renal adjustment needed 6. No reversal agent available 7. Alternative to bivalirudin in PCI 8. Lower dose in hepatic impairment