More worries about blood thinner

The scope of concerns about the possible ill effects of a contaminated blood thinner from China grew significantly Tuesday as federal regulators urged makers of many kinds of medical devices that contain the drug to test their supplies.

The products to be tested cover a spectrum of equipment and uses. They include kits that flush out intravenous lines, drug-coated stents for opening clogged arteries and certain diagnostic tests that use heparin and could deliver inaccurate results if contaminated.

Food and Drug Administration spokeswoman Karen Riley said the recommendation was “largely a precautionary move.”

The agency has received two reports of serious allergic reactions linked to medical devices that contained heparin. The reactions to the blood thinner are similar to those seen in some patients who received intravenous heparin that was recalled this year. Riley said the FDA would send letters to 82 medical device manufacturers urging them to test their heparin.

“We are aware that some of these products have been affected by the recent contamination,” Riley said.

Separately, the FDA released statistics on deaths linked to intravenous heparin, the form of the drug in which problems were first detected. The numbers showed an increase in fatalities from November 2007 through February 2008, with problems rapidly abating last month after Baxter Healthcare Corp. issued a recall.

Many of the patients who receive the blood thinner are already in fragile condition, and some can experience severe side effects even if the drug is pure. The particular side effect that investigators are focusing on is a severe allergic reaction that can lead to a sudden and highly dangerous drop in blood pressure.

The statistics showed that the number of reported deaths jumped from two in October -- a fairly typical number -- to eight in November, and reached a peak of 16 in January. It was the sudden increase in such reports that prompted Baxter to alert the FDA to the problem.

The FDA’s statistics showed 62 deaths associated with the severe reaction in the 15 months from January 2007 through last month -- an increase from the agency’s previous count. Of these reported deaths, 47 came in the four-month period in which reports of problems suddenly shot up. Baxter contends that none of the deaths have been conclusively tied to its product.

China is the world’s leading supplier of heparin, a blood thinner often made from a substance in the intestines of pigs. It is commonly given to prevent blood clots in heart surgery and dialysis patients.

Baxter’s heparin was contaminated with a look-alike ingredient that mimicked heparin in standard tests of drug potency and purity.

The FDA announced last month that it had identified the contaminant as a modified form of a common nutritional supplement. That substance is cheaper to produce than heparin, leading to suspicions that it may have been intentionally added somewhere along a complex and lightly regulated supply chain in China.

The look-alike substance was identified using special tests, which the FDA is now asking medical device manufacturers to employ.

Riley said the agency was recommending that doctors and hospitals be alert to any serious side effects in patients using medical devices that contain heparin and be prepared to deliver emergency treatment. The FDA also urged doctors to be on the lookout for any puzzling test results in diagnostic kits that use heparin.

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ricardo.alonso-zaldivar@latimes.com