Heparin likely weaker, but safer

Beginning this week, a manufacturing change to the anti-clotting drug heparin will likely decrease its potency, according to an FDA alert.

As a hedge against contamination, following a Baxter recall traced to active ingredient contamination at a plant in China, the United States Pharmacopeia (USP) has adopted new manufacturing controls, which include a modification of the reference standard for the drug's unit dose. The changes match those of the World Health Organization's International Standard (IS) unit dose definition in use in Europe. The revised reference standard and unit definition for heparin is about 10 percent less potent than the former version.

The FDA says that manufacturers for the U.S. market have begun to make heparin using the new USP standard, which became effective October 1, 2009, for production. At FDA request, however, manufacturers have held shipments until at least October 8 to give health care providers and facilities time to make adjustments.

- here's the FDA alert