Heparin: Change in Reference Standard- New Universal Standardization in Heparin Potency
April 8, 2010
FDA released new testing methods and standards to check heparin for potency and impurities. These changes decrease US marketed heparin potency by approximately 10% and standardize the United States Pharmacopeia (USP) unit dose with the World Health Organization international unit dose. A new USP monograph was developed for the new heparin potency. The first availability of the new potency heparin is expected on or after October 8, 2009. FDA is working to ensure manufacturers distinguish between the old and new heparin products. Most manufacturers plan to place an “N” by the lot number or expiration date of the new potency products to help distinguish them from the old potency lots.
No difference in clinical significance is expected with subcutaneous administration of the new potency product. The change in heparin potency may impact bolus and maintenance intravenous dosing; however, FDA recommended the dosing for heparin remain the same. Continue to monitor anticoagulation parameters. Use clinical judgement considering the change in heparin potency when adjusting heparin doses to achieve the desired anticoagulation effect. Some clinical circumstances, including aggressive anticoagulation, may necessitate heparin dosage adjustments and more frequent monitoring.
Additional information is available at the following links:
- FDA Public Health Alert (updated 04/07/2010):
- MedWatch Alert:
- FDA Public Health Alert (10/01/2009):
- FDA Information for Consumers:
April 8, 2010; October 5, 2009; University of Utah, Drug Information Service. Copyright 2010, Drug Information Service, University of Utah, Salt Lake City, UT.