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FDA: Prussian Blue as Tmt for Exposure to Radioactive Exposures
FOR IMMEDIATE RELEASE
PO3-06
January 31, 2003
Media Inquiries: 301-827-6242
Consumer Inquiries: 888-INFO-FDA
FDA ENCOURAGES NEW DRUG APPLICATION SUBMISSIONS FOR PRUSSIAN BLUE AS A
TREATMENT FOR THALLIUM OR RADIOACTIVE CESIUM CONTAMINATION
Today the Food and Drug Administration (FDA) called for manufacturers to
submit marketing applications for Prussian blue, a mineral compound
known as ferric hexacyanoferrate(II), that has been shown to be safe and
effective in treating people exposed to radioactive elements such as
cesium-137.
"Today's action is part of our continuing effort to foster the
development and availability of countermeasures to terrorist attacks,"
said Tommy G. Thompson, Secretary of the Department of Health and Human
Services, "We must and will do more to prepare and protect Americans
against the threat of bioterrorism."
After a review of cases in published literature, FDA determined that
500-mg. Prussian blue capsules would be safe and effective for the
treatment of patients with known or suspected internal contamination
with radioactive thallium, non-radioactive thallium, or radioactive
cesium. At this time, there are no FDA-approved treatments for internal
contamination with thallium or radioactive cesium.
Prussian blue is the first therapy that would be available to
immediately help reduce the body’s burden of exposure to radioactive
particles (isotopes). By binding with the radioactive particles while
they are in the gut, Prussian blue captures the isotopes and causes them
to be eliminated from the body.
“FDA is working to protect U.S. citizens who may be exposed to
radioactive materials released from terrorist attacks using a
dirty-bomb,” said Dr. Mark B. McClellan, FDA Commissioner. “FDA’s
guidance to industry and approved labeling for Prussian blue products
gives manufacturers critical information necessary for producing an
FDA-approved product to counter terrorism.”
Cesium-137 is a product found in the fallout from the detonation of
nuclear weapons and in the waste from nuclear power plants. In
appropriate doses, it is also used as a source of radiation for cancer
treatments. Cesium-137 contamination can cause serious illness or death
and has been associated with cancer occurring long after exposure.
In addition to concerns about accidental industrial and medical
exposure, cesium-137 is of particular concern because it is a potential
component of a conventional explosive device (a “dirty bomb”) containing
radioactive material. Although this radiological dispersal device is not
a nuclear bomb, it is detonated as a means to spread radioactive
material.
In determining the safety and effectiveness of Prussian blue, FDA
evaluated reports of a 1987 incident in Brazil, where 250 people were
contaminated with cesium-137 that had been abandoned after use in a
cancer clinic. The reports showed that Prussian blue reduced the time
the body was contaminated with cesium-137. Additional data from the
literature, including a study of 7 human volunteers contaminated with
trace doses of cesium-137, and reports on 19 patients in other incidents
show a similar reduction in the biological half-life of the cesium after
Prussian blue administration New Drug Applications.
Thallium, occurring naturally in several minerals and ores, is very
toxic. In the form of thallium sulfate, it has previously been used as a
rat and ant poison, while other thallium compounds are still used in
manufacturing semiconductors, photocells, and optical glass.
Thallium-201, a radioactive isotope of thallium, is used in small doses
as a radio-imaging agent in clinical diagnostic procedures. Exposure to
higher doses of radioactive or non-radioactive thallium causes severe
gastrointestinal symptoms followed by neurological symptoms, which may
cause death.
The main side effects of Prussian blue are constipation and nonspecific
gastrointestinal distress. Other rare adverse events are discussed in
the published literature and in the draft labeling the agency prepared.
Prussian blue was first synthesized in 1704 and has been used as an
industrial and artist’s pigment since 1724. It has been used
experimentally since the 1960s as an orally ingested drug to increase
fecal excretion of cesium and thallium from the body without it being
absorbed through the intestines in the process.
FDA encourages the submission of New Drug Applications for Prussian blue
drug products, which when produced under the conditions specified in the
Federal Register notice assures that the product is safe and effective.
Because the FDA has already completed the safety and efficacy review
work, applicants need only to submit the chemistry information for the
Prussian blue product they make. To facilitate the process, the agency
has prepared draft labeling and has published a guidance document on how
to submit these applications.
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.....................................................
Susan L. Gawarecki, Ph.D., Executive Director
Oak Ridge Reservation Local Oversight Committee
102 Robertsville Road, Suite B, Oak Ridge, TN 37830
Toll free 888-770-3073 ~ www.local-oversight.org
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