The US Food and Drug Administration announced Friday that they may soon be able to identify a contaminant found in 20 of 28 samples (over 70 percent) of an active ingredient used in producing heparin. The ingredient was produced in China.

The FDA said that once they know exactly the nature of this ‘heparin-like’ contaminant, it is likely they can also determine whether this was introduced deliberately into the ingredient or produced unintentionally during processing.

Heparin is a generic drug used as a blood thinner, to prevent it from clotting, during surgical procedures and also for hemo-dialysis.

Heparin supplied by Baxter International was recalled in mid-January after it was linked to hundreds of allergic reactions. Since the end of December, the number of allergic reactions reported has reached 785; this is huge, because in all of 2007, there were fewer than 100 incidences reported. At least 4 deaths have also been clearly linked to this adverse reaction to the drug.

The majority of these reactions occurred at hemo-dialysis centers, where the procedure involves administering a high dose within a relatively short period of time. The adverse reactions may be nausea/vomiting, breathing difficulty, heavy sweating, and rapid decrease in blood pressure, which may cause life-threatening shock.

The heparin-like contaminant has very similar molecular structure to and acts like heparin in conventional tests. This is the reason the contaminant did not show up in routine purity testing. It was detected only through the use of nuclear magnetic resonance spectroscopy and capillary electrophoresis.

Heparin is processed from tissues in the lining of pig intestines. China is the world’s main source of the active ingredient in heparin because of its huge pig population. Most of the supply originates from family-run workshops located close to slaughterhouses. The raw material is delivered to bigger consolidators, who then ship to plants in Changzhou, in the outskirts of Shanghai.

This brings forward the possibility that the problem may have started somewhere along the supply chain. The FDA said that once they have identified contaminant, they can trace where along this chain the contamination occurred.

At this point, the FDA is not sure whether this contaminant is causing all of the allergic reactions that have been reported. This will have to be determined through further testing. Heparin has been used by Americans since the 1930’s. Allergic reactions have been reported in rare instances before, but since December there has been a sharp increase in the number of reactions reported.

Safety Tip:

• Ask for heparin produced by the other major supplier (APP Pharmaceuticals). There have been no adverse reactions associated with their heparin.

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