Heparin Considerations for Use*

Non-FDA Approved Indication: Alternative to Oral Anticoagulation for Stroke Prevention in Atrial Fibrillation

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Mechanism of Action

Inhibits thrombin and factor Xa


Adult: 70 units/kg bolus, then 15 units/kg/hr infusion; adjust dose based on aPTT and hospital’s nomogram2

Elderly: No specific dosage adjustment

Hepatic Impairment: No specific dosage adjustment

Renal Impairment: No specific dosage adjustment


Active pathological bleeding, thrombocytopenia, history of heparin-induced thrombocytopenia

Major Side Effects

Hemorrhagic event, heparin-induced thrombocytopenia

Dosage forms and Strengths

IV: solution for injection


Discontinue heparin. Anticoagulation effects should be minimized within 3 hours; evaluate aPTT to confirm.

Protamine, given as a slow IV infusion (1 % solution), may largely neutralize heparin. Protamine 1 mg neutralizes ~ 100 units of heparin. Do not exceed protamine 50 mg. Monitor aPTT to confirm neutralization.

Conversion to/from other drugs

From heparin to warfarin:

  • Initiate warfarin when appropriate (usually start on same day as heparin).
  • Continue heparin until INR is within therapeutic range for at least 2 days.
  • Special Notes

    Monitor aPTT, hemoglobin, hematocrit, platelets, stool for occult blood based on hospital’s nomogram.

    May monitor anti-Xa (goal 0.3 to 0.7 IU/mL antifact or Xa activity) as an alternative to aPTT monitoring.

    May reverse anticoagulation effects with protamine.

    Discontinue all heparin products when heparin induced thrombocytopenia is suspected or diagnosed.


    Report signs and symptoms of bleeding (e.g., unexpected bleeding or bleeding that lasts a long time; red or black, tarry stool; pink or brown urine; unusual bruising; coughing up blood; vomiting blood or vomit that looks like coffee grounds; unexplained pain, swelling, or joint pain; unusual headaches, dizziness, or weakness; recurring nose bleeds)

    *Refer to prescribing information for more complete information.
    †Dosages given in the table may differ from those recommended by the manufacturers.


    1. American College of Cardiology (ACC), American Heart Association (AHA), and Heart Rhythm Society (HRS). 2011 ACCF/AHA/HRS Focused Update on the Management of Patients With Atrial Fibrillation (Update on Dabigatran). Washington, DC: American College of Cardiology Foundation. 2011.
    2. Chest Supplement, Antithrombotic Therapy and Prevention of Thrombosis, 9th edition, American College of Chest Physicians.