Bleeding Patients on Dabigatran aka Pradaxa

By Dr. Ling Zang, MD

Please refer to

Indication: stroke prevention in atrial fibrillation

Mechanism of action: reversible, competitive, direct thrombin inhibitor (downstream from other anticoagulants)

Pharmacokinetics:

  • Half time: 13 hours in patients with normal renal function (Cr clearance > 80%), up to 28 hours in those with renal function impairment (Cr clearance < 30%)
  • Peak effect: 2-3 hours
  • Excretion: renal

 

Why it is preferred over Coumadin:

  • more predictable pharmacokinetics
  • no CYP450 interaction
  • one dose for all patients
  • no monitoring
  • Similar to – if not better than – Coumadin in stroke prevention as an outcome

 

How to measure the anticoagulation effect of Dabigatran?

  • Thrombin time – very sensitive, but not standardized
  • aPTT – sensitive, but underestimates level of anticoagulation at high doses
  • INR – not useful as it only cause mild elevation even at high doses

 

Which agents could be used to reverse Dabigatran?

  • Vit K – allows synthesis of clotting factors, upstream from Dabigatran, won’t work.
  • FFP – contains all clotting factors, including thrombin.  Consider using.
  • PCC – contains some factors and some thrombin. Consider using.
  • Factor VIIa – can directly activate thrombin.  Considering using.

Or…Dialysis:

At 2 hours, about 62% of Dabigatran will be removed.

 

Approach to a bleeding patient on Dabigatran

  1. Assess the severity of bleeding
  2. Determine timing of last dose of Dabigatran to see if patient is being anticoagulated by it
  3. Hemorrhage control
  4. Draw aPTT and TT.  If normal, it is unlikely that the patient has significant anticoagulation
  5. Consider FFP, Factor VIIa, and dialysis.  If last dose is within 2 hours, give activated charcoal.
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