New USP Standards for Heparin Products Will Result in Decreased Potency Adjustments may be needed to achieve desired anticoagulant effect in some patients.

The U.S. Food and Drug Administration today alerted health care professionals to a change in heparin manufacturing that is expected to decrease the potency of the common blood-clotting drug.

To ensure the quality of heparin and to guard against potential contamination, the United States Pharmacopeia (USP), a nonprofit standards-setting organization, adopted new manufacturing controls for heparin. These changes include a modification of the reference standard for the drug’s unit dose.

Manufacturers in the United States label the amount of heparin included in their products based on USP standards. The changes adopted by the USP for the heparin unit dose match the World Health Organization’s International Standard (IS) unit dose definition that has been in use in Europe for many years. The revised USP reference standard and unit definition for heparin is about 10 percent less potent than the former USP unit.

FDA Alert to Health Care Professionals

USP Heparin Information

Information for Consumers: What You Should Know about Changes to Heparin