By Amanda Gardner
THURSDAY, Oct. 1 (HealthDay News) -- U.S. health officials on Thursday announced new manufacturing standards for the widely used blood-thinner heparin that will decrease the drug's potency by about 10 percent.
The reformulation is largely a response to contaminated heparin that came from China in 2007-2008 and caused hundreds of severe reactions and 200 deaths among U.S. patients, most of whom were on kidney dialysis.
While the new standards take effect Oct. 1, the four U.S. manufacturers of heparin have already started making units under the new guidelines, which will make it easier to spot impurities.
But the U.S. Food and Drug Administration (FDA) has asked them to delay shipment of the new formula until Oct. 8 to allow health-care providers to come up to speed on the changes.
The decrease in potency is likely to affect some clinical situations more than others, Dr. John K. Jenkins, director of the Office of New Drugs at the FDA's Center for Drug Evaluation and Research (CDER), said at a news conference.
For example, he explained, when the blood thinner is "administered as a bolus intravenous dose and an immediate anti-coagulant effect is clinically important," health-care providers should consider the decrease in potency when making decisions about the dosage needed.
"The change in potency is expected to be less clinically significant when administered subcutaneously," Jenkins added.
The FDA will be conducting tests to determine the exact clinical impact of the lower potency, officials said.
The changes do not affect labeling of the blood thinner, which is derived from pig intestines and used to prevent blood clots during certain kinds of surgery, and by people requiring kidney dialysis.
While the transition is taking place, both old and new versions of heparin will be available. New lots will be identified by either the letter "N" placed next to the lot number or expiration date (three manufacturers) or a numeric code (one manufacturer).
The correct dosing of heparin has always been highly individualized and requires intense monitoring, which is a protocol that will remain in effect, officials said.
"The use of heparin is closely tied into monitoring and doses adjusted based on that," said Dr. Dwaine Rieves, director of CDER's Division of Medical Imaging and Hematology Products. "That procedure will not change."
The standards were changed to include a specific chemical identification of heparin that more precisely spots the chemicals in the drug.
They were created by the U.S. Pharmacopeia Convention, a nonprofit health organization that sets public standards for prescription and over-the-counter medicines and other health-care products made or sold in the United States.
The contaminated heparin from China was tainted with man-made over-sulfated chondroitin sulfate, which comes from the dietary supplement chondroitin and mimics heparin's blood-thinning properties.
Learn more about heparin at the U.S. Pharmacopeia.
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