Warning about deaths and serious reactions linked to blood thinning drug heparin

The Food and Drug Administration (FDA) in the United States says the production of a popular blood thinning drug has been halted temporarily after more than 300 reports of health problems associated with the drug.

Multi-dose vials of the blood-thinner heparin produced by Baxter International have been linked to four deaths and hundreds of cases of sickness including difficulty breathing, nausea, vomiting, excessive sweating and rapid drop in blood pressure, since the end of 2007.

The majority of the cases occurred at kidney dialysis centers but other cases have included patients undergoing heart surgery or a specialized blood cell treatment called photopheresis.

Heparin sodium is derived from pig intestines and has been used in Australia for decades mainly in a hospital setting.

The FDA has advised doctors to use an alternative source of heparin or another blood-thinning agent where possible and is investigating whether similar problems have been seen with heparin made by other manufacturers.

Baxter International makes about half of all multiple-dose vials of heparin sold in the United States and millions of patients are given the product intravenously each year.

Serious allergic reactions and hypotension (low blood pressure) were reported in patients who were given a "bolus" dose, or a high dose over a short period of time.

Heparin has been widely used since the 1930s in operating rooms and other critical care areas to prevent blood clots and is important in hemodialysis and heart surgery to avoid potentially life-threatening blood clots in the veins, arteries, and lungs.

Heparin is commonly used prior to certain types of surgery, including coronary artery bypass graft surgery, and in kidney patients before they undergo dialysis.

In some situations, heparin treatment is sometimes given intravenously as a high bolus dose directly into the bloodstream over a short period of time, and it is in such situations that the adverse events occurred.

The FDA says adverse events were not seen in patients who received lower doses of the drug or who received higher doses spread over a longer period of time.

In January Baxter voluntarily recalled nine lots of its injectable heparin sodium injection in 1000-unit vials, citing an increase in adverse patient reactions and since then the company has received reports of adverse reactions in multi-dose vials of 1000 units, 5000 units and 10,000 units, and in single-dose vials of 5000 units when single doses were combined to create a larger bolus dose.

Because of this the company has temporarily suspended the manufacture of multi-dose heparin vials as it investigates the cause of the increase in adverse reactions.

To avoid causing a shortage of supply and create more risk to patients requiring heparin therapy Baxter is not recalling any additional lots of heparin.

Dr. Janet Woodcock, the FDA's deputy commissioner for scientific and medical programs, says the agency is vigorously investigating the cause of the serious reactions associated with the use of Baxter's heparin.

Dr. Woodcock says in the meantime, patients and health care professionals who cannot obtain alternative sources of heparin should use caution in administering any Baxter multiple-dose vials.