Prussian blue (also known as Berlin blue or, in painting, Parisian or Paris blue) is a dark blue pigment produced by oxidation of ferrous ferrocyanide salts. It has the molecular formula Fe4[Fe(CN)6]3 or C18Fe7N18 Turnbull’s blue is chemically identical, but is made from different reagents, and its slightly different color stems from different impurities.
Prussian blue was the first modern synthetic pigment. It is prepared as a very fine colloidal dispersion, because the compound is not soluble in water. It contains variable amounts of other ions and its appearance depends sensitively on the size of the colloidal particles. The pigment is used in paints, and it is the traditional “blue” in blueprints and aizuri-e (藍摺り絵) Japanese woodblock prints.
In medicine, orally administered Prussian blue is used as an antidote for certain kinds of heavy metal poisoning, e.g., by thallium(I) and radioactive isotopes of caesium. The therapy exploits the compound’s ion-exchange properties and high affinity for certain “soft” metal cations.
It is on the World Health Organization’s List of Essential Medicines, the most important medications needed in a basic health system. Prussian blue lent its name to prussic acid (hydrogen cyanide) derived from it. In German, hydrogen cyanide is called Blausäure (“blue acid”). French chemist Joseph Louis Gay-Lussac gave cyanide its name, from the Ancient Greek word κύανος (kyanos, “blue”), because of its Prussian blue color.
Indicated for treatment of patients with known or suspected internal contamination with radioactive cesium and/or radioactive or non-radioactive thallium to increase their rates of elimination.
Mechanism of action
Prussian blue traps radioactive cesium and thallium in the intestines to keep them from being absorbed by the body.
These radioactive materials move through the intestines and pass out of the body (excrete) in bowel movements. Getting these materials out of the body help limit the amount of time they expose the body to radiation.
Prussian blue reduces the biological half-life of cesium from about 110 days to about 30 days. The biological half-life is the amount of time it takes for the radioactive material to leave the body, which decreases its harm.
Prussian blue reduces the biological half-life of thallium from about 8 days to about 3 days.
Who can take Prussian blue?
The drug is safe for most adults, including pregnant women, and children (2-12 years). Experts have not yet determined dosing for infants (ages newborn-2years)
Before you take Prussian blue talk to your doctor if you have
- blockages in the intestines
- other stomach problems
Before taking Prussian blue, you should tell your doctor about any medicines you are taking.
How is Prussian blue given?
Prussian blue comes in 500-milligram capsules that patients can swallow whole. If you cannot swallow pills, you can break the capsule and mix the contents in food or liquid. This may cause your mouth or teeth to turn blue during treatment.
Prussian blue insoluble is administered to decrease radiation exposure. It does not treat the complications of radiation exposure. Patients contaminated with high doses of 137-Cs may develop radiation toxicity including bone marrow suppression with severe neutropenia and thrombocytopenia. Supportive treatment for radiation toxicity symptoms should be given concomitantly with Prussian blue insoluble treatment.
In radiological emergencies, the type of elemental exposure may not be known. Prussian blue insoluble may not bind to all radioactive elements and some radioactive elements may not undergo enterohepatic circulation, which is needed for Prussian blue insoluble binding and elimination. Patients contaminated with unknown or multiple radioactive elements may require treatment with other agents in addition to Prussian blue insoluble
Prussian blue insoluble can cause constipation. Decreased gastrointestinal motility will slow the transit time of 137-Cs bound to Prussian blue insoluble in the gastrointestinal tract, and may increase the radiation absorbed dose to the gastrointestinal mucosa. Constipation occurring during Prussian blue insoluble treatment may be treated with a fiber based laxative and/or a high fiber diet. Prussian blue insoluble should be used with caution in patients with disorders associated with decreased gastrointestinal motility.
In patients who cannot swallow capsules, when the capsules are opened and the contents are mixed with food and eaten, the mouth and teeth might be colored blue.
Prussian blue side effects
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
- severe constipation; or
- severe stomach pain.
Prussian blue may cause your stools to appear blue in color. This is a normal side effect of Prussian blue, and should not be cause for alarm.
Common side effects may include:
- constipation; or
- stomach discomfort.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects
Where can I get Prussian blue?
You can only obtain Prussian blue by prescription.
People SHOULD NOT take Prussian blue artist’s dye in an attempt to treat themselves. This type of Prussian blue is not a treatment for radioactive contamination and can be harmful.
More detailed information on Prussian blue can be found at the FDA Website