Contaminated heparin investigated in the US

A batch of heparin, a blood-thinning drug used in dialysis and other treatments, has come under investigation in the US after the Food and Drug Administration (FDA) reported of up to 81 deaths and hundreds of severe allergic reactions related to the drug containing China-sourced components.

The FDA said it suspects the raw components may have contained a possibly counterfeit ingredient that mimics heparin so closely that routine tests can't detect it, AP writes.

"At this point, we do not know whether the introduction was accidental or whether it was deliberate," Deputy FDA Commissioner Janet Woodcock told International Herald Tribune.

According to Jin Shaohong, deputy director of China's National Institute for the Control of Pharmaceutical and Biological Products, further analysis is needed to decide the relationship between the substance and the deaths. "The direct causal relationship between the heparin substitute (hypersulphated chondroitin sulphate) and the clinical cases of deaths cannot yet be confirmed," Xinhua quotes him as saying.

Meanwhile, US experts have been able to find a link between large doses and quick injecting speed, and adverse reactions, Jin added.

Apart from the US and Germany, more than 10 countries using heparin products containing the discovered "heparin-like substance" had not reported adverse reactions, Jin told Xinhua. In addition, such reactions have also been encountered in people receiving heparin injections that did not contain the suspected counterfeit ingredient, he added.

The raw components for the drugs manufactured by Baxter International, the US drug maker that recalled the batches of heparin, were supplied by a factory owned by US-based Scientific Protein Laboratories (SPL), located in Changzhou, Jiangsu Province, Xinhua writes.

A team of Chinese experts was deployed to investigate the contamination. However, Baxter International failed to cooperate with the experts, refusing to provide timely details on victims and specifics about production, Jin says.

Erin Gardiner, spokeswoman for Baxter, asserts that the company cooperated with all parties involved, AP writes.

When adverse events are reported in the US, the relevant patient records will be posted on the FDA's website with the personal details withheld, FDA spokeswoman Karen Riley told AP, adding that details involving the heparin cases should be posted in June.

According to Wayne Pines, a spokesman for SPL, the contamination has not been proven to be intentional. "There is no evidence of counterfeiting or tampering or anything of that nature," she told International Herald Tribune.

The FDA has now received 785 reports of serious adverse reactions associated with the drug's use. Nearly all of Baxter's heparin production has been recalled pending investigation.