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Podcast for Healthcare Professionals: Follow up to the Public Health Alert about Changes to the Heparin Sodium USP Monograph

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Welcome, my name is Chris Jones, a pharmacist in the Division of Drug Information. Today I am updating you on a follow-up to an October 2009 Public Health Alert about changes to the United States Pharmacopeia or USP monograph for heparin sodium.

At FDA's request, laboratory studies were conducted to better understand the clinical impact of the change in potency for heparin after the new monograph went into effect in October 2009.

The studies performed in animals and in human plasma have shown that heparin made under the new USP monograph, called "new heparin," has approximately 10% less anticoagulant activity compared to heparin made under the previous USP monograph, called "old heparin." The average activated partial thromboplastin time (aPTT) response to a dose of heparin changed in a dose- proportional manner.

The studies also demonstrated that there were large individual variations in aPTT responses to a given dose of heparin. Therefore, in a clinical setting, a 10% decrease in heparin dose might not be reflected in the results of an aPTT or Activated Clotting Time for an individual patient.

Given the inherent individual variability in response to a dose of heparin, a 10% decrease in heparin activity is not likely to have clinical significance. However, special clinical situations such as cardiac surgery or use in pediatric patients may require more intensive monitoring to achieve optimal therapeutic response. Since heparin therapy is routinely titrated to each patient the usual method of individualizing dosing will continue to ensure patient safety.


The results of these studies reinforce FDA's previous recommendation for healthcare professionals to exercise clinical judgment in determining the dose of heparin for a patient and consider the clinical circumstances where the potency decrease may require dosage adjustments and more frequent monitoring.

FDA recommends that healthcare professionals:

1. Be aware that there is an approximate 10% decrease in the anticoagulant activity of "new heparin" compared to "old heparin." However, the labeling for heparin, including the recommended doses, has not changed.

2. Continue to exercise clinical judgment in determining the individual dose of heparin for specific patient clinical situations.

3. Consider those clinical circumstances where the potency decrease may require dosage adjustments and more frequent monitoring, such as where aggressive anticoagulation is essential to the treatment of the patient, including:

  • pediatric patients undergoing extracorporeal membrane oxygenation
  • adults and children undergoing cardiopulmonary bypass
  • the treatment or prevention of life-threatening thromboses

4. Be aware that both old and new heparin may be available for some time. Consider not using the products interchangeably. Pharmacies and hospitals may wish to consider separating the supplies of old and new heparin and exhausting the supplies of "old" heparin before transitioning to the "new" product. Refer to the table on FDA's website entitled, "How to Identify Heparin Products made to the New USP Standard" for additional information on how to identify old and new heparin.

5. Report any adverse events with the use of Heparin to FDA's Medwatch program at www.fda.gov/medwatch.

Thank you for listening. The FDA is committed to keeping healthcare professionals informed of the latest safety information. If you have questions about this safety communication, you can reach the Division of Drug Information at the following email address: druginfo@fda.hhs.gov.


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