FDA Warns that New Heparin Will be Less Potent to Improve Safety

The FDA has alerted health care professionals that new batches of the blood thinner Heparin will be less potent than previous versions due to new safety standards, which are designed to make it easier for manufacturers to ensure the purity of the drug and help avoid a repeat of the widespread heparin contamination that sickened hundreds of people in late 2007 and early 2008.

Heparin has been reformulated to make it easier to detect impurities, but the new formula is about 10% less potent than those most doctors are used to working with, the FDA warned in an October 1 press release.

The reformulation follows an outbreak of heparin reactions nearly two years ago that was linked to tainted blood thinner made from a counterfeit ingredient received from a manufacturing plant in China. A heparin recall was issued in January 2008 by Baxter Healthcare, which impacted about half of the injectable heparin sold in the United States and has been linked to more than 80 heparin deaths.

In addition to allowing easier testing for impurities, the changes will also bring dosage in the United States into harmony with the World Health Organization (WHO) International Standard unit dose.

The FDA indicates doctors need to take the reduction of potency into account when using the drug. In addition, both the old and new versions of heparin will be on the market at the same time, in order to prevent a supply problem, which may cause some confusion.

Manufacturers are expected to place an “N” next to the lot number to differentiate the new formula from the old one.