The US FDA has recently reported cases of anaphylaxis associated with the use of intravenous heparin.
Testing by the FDA of samples associated with these adverse reactions has identified the presence of a contaminant known as 'over-sulphated chondroitin' within the heparin.
As a result of these reports the TGA has tested all brands of heparin sodium available on the Australian market for the detection of the contaminant.
The TGA has completed its testing of heparin sodium products currently distributed in Australia by Astra Zeneca, Hospira, Pfizer and Baxter.
Only Astra Zeneca's heparinised saline product has been found to contain this contaminant. Astra Zeneca has recalled affected batches.
The TGA considers it is appropriate for the intravenous heparin sodium products found to be free from over-sulphated chondroitin to continue to be supplied and used.
Testing of low molecular weight heparins (which are produced by breaking down heparin into smaller molecular components by a process known as fractionation) is ongoing. To date, the TGA has completed its testing of low molecular weight heparin manufactured by Pfizer and this was found to be clear of over-sulphated chondroitin. Testing of the Sanofi-Aventis low molecular weight heparin is ongoing.
The TGA's testing program for heparin products has also revealed that some heparin sodium products contain the substance dermatan. Dermatan belongs to the group of substances known as glycosaminoglycans, which includes heparin and heparin sulphate. Dermatan is a naturally occurring substance found in the skin and connective tissue of virtually all mammalian tissues. It has been present in some heparin products in Australia and internationally for many years.
The heparin ingredients used to manufacture heparin sodium products are sourced from several locations in China. To ensure future batches of heparin sodium products supplied in Australia remain free from over-sulphated chondroitin, the TGA will require that the Australian supplier ensures that all lots of heparin material must be tested and shown to be free from the contaminant before they can be used.
At this stage the total number of reports of anaphylaxis in the USA remains relatively small and to date the TGA has not received an increased number of reports associated with use of heparin here in Australia.
Also, a causal link between the presence of over-sulphated chondroitin and the adverse events has not been firmly established. Therefore, TGA's advice to health professionals continues to be:
- use heparin only where it is medically essential after careful weighing of the risks and benefits for each individual patient;
- carefully monitor patients during and immediately following heparin administration for signs of allergy or anaphylactic reaction;
- report any adverse events associated with the use of heparin to the TGA.
Any concerns or adverse events associated with the use of heparin products should be reported to the TGA's Adverse Drug Reactions Unit at the following web address Australian Adverse Drug Reaction Reporting System or via email to adr.reports@tga.gov.au.