Anticoagulation Reversal

UFH (IV heparin)

• Protamine (max 50 mg):

  • 0–30 min: 1 mg / 100 units

  • 30–60 min: 0.75 mg / 100 units

  • 60–120 min: 0.5 mg / 100 units

  • 2 hr: 0.25–0.375 mg / 100 units

• Give slow IV ≥10 min

• Redose if bleeding + ↑ aPTT

LMWH (enoxaparin, dalteparin) (partial reversal ~60–75%)

• Enoxaparin:

  • <8 hr: 1 mg protamine / 1 mg enoxaparin

  • 8–12 hr: 0.5 mg / 1 mg

  • 12 hr: usually none

• Repeat: 0.5 mg/kg if bleeding persists

DTI / DOAC

• DTI (argatroban, bivalirudin): stop infusion

• Dabigatran: idarucizumab 5 g IV (repeat if rebleed + ↑ aPTT; charcoal if <2 hr ingestion)

• Factor Xa inhibitors: PCC 2000 units IV (repeat if needed; use for emergent surgery)

Warfarin

Major bleed / emergent surgery

• Vitamin K 10 mg IV + PCC

  • Non-ICH: 1500–2000 units

  • ICH: 2000–2500 units

• Redose PCC +500 units if INR >1.5 or ongoing bleed

• Check INR: 30 min → q6h x24h (do not delay PCC)

INR >10

• ± bleeding: Vitamin K 2.5–5 mg PO (or 1–5 mg IV)

• Recheck INR in 24 hr

INR 4.5–10

• Bleeding: hold warfarin + Vitamin K 1–2.5 mg PO

• No bleeding: hold warfarin (± Vitamin K if high risk)

Special

• Mechanical valve / LVAD: avoid Vitamin K if possible

• Low bleeding risk: hold warfarin only