Thallium Prussian Blue

For children exposed to cesium-137 and thallium, Prussian blue is administered. Prussian blue enhances the excretion of these agents in the stool, thereby decreasing radiation exposure (Chung Shannon, 2005). The dosage for Prussian blue is 3-10 g/day by mouth (0.21-0.32 g/kg/day) (Columbia University Mailman School of Public Health National Center for Disaster Preparedness, 2005). Complications and side effects from the radiation exposure will require the standard treatment. 

Just a few years after the discovery of the deposition and electroactivity of Prussian blue, other metal hexacyanoferrates were deposited on various electrode surfaces. However, except for ruthenium and osmium, the electroplating of the metal or its anodizing was required for the deposition of nickel [14], copper [15,16], and silver [9] hexacyanoferrates. Later studies have shown the possibilities of the synthesis of nickel, cobalt, indium hexacyanoferrates similar to the deposition of Prussian blue [17-19], as well as palladium [20-22], zinc [23, 24], lanthanum [25-27], vanadium [28], silver [29], and thallium [30] hexacyanoferrates. 

H. Kahlert, S. Komorsky-Lovric, M. Hermes, and F. Scholz, Prussian blue-based reactive electrode (reactrode) for the determination of thallium ions. Fresenius J. Anal. Chem. 356, 204-208 (1996). 

J.M. Zen, H. Ho, and P.Y. Chen, Voltammetric determination of thallium on a Prussian blue/cinder paste electrode. Indian J. Chem. Sect. A Inorgan. Bio-Inorgan. Phys. Theoret. Anal. Chem. 42, 839—842 (2003). 

Prussian yellow. This irreversible binding of thallium(I) ions is probably related to the well-known use of Prussian blue to bind thallium ions following poisoning. 

In 2003, the FDA approved Prussian blue for the treatment of contamination with radioactive cesium (137Cs) and intoxication with thallium salts. Approval was prompted by concern over potential widespread human contamination with radioactive cesium caused by terrorist use of a radioactive dispersal device ("dirty bomb"). The drug is part of the Strategic National Stockpile of pharmaceuticals and medical material maintained by the CDC... 

Thompson DF, Called ED Soluble or insoluble Prussian blue for radiocesium and thallium poisoning Ann Pharmacother 2004 38 1509. [PMID 15252192]... 

The treatment of thallium poisoning is rather ingenious. It takes three forms diuretics eliminate thallium through increased urine production Prussian blue dye traps thallium excreted into the gut, preventing its reabsorption and potassium chloride supplements displace the thallium that has already been absorbed into the tissues. These measures allowed the unfortunate child from Qatar to make a complete recovery. 

Of course, what the students are really interested in is why thallium is poisonous. Surprisingly, thallium is toxic because it mimics potassium in the body. But why would thallium behave like potassium As we study the periodic table and chemical periodicity, there is no immediate reason to suspect that these two elements would have similar properties. A close look at the electron shell arrangement of thallium and potassium, however, reveals that both form +1 ions. Since Tl+ ions also happen to be similar in size to K+ ions, they are able to replace potassium ions in cellular processes. (Thallium poisoning is treated with a compound called Prussian blue, which binds to +1 ions and thus facilitates their removal from the body.) It is clear then that we cannot understand the toxicity of thallium without studying its atomic structure and electron distribution. But chemistry is only part of the story. The effects of thallium poisoning only make sense if the... 

Thallium, atomic no. 81 This element is better known for its poisonous properties and links with almost undetected deaths and Agatha Christie -type murder mysteries.2 Thallium compounds are used in some countries as cheap insecticides, particularly for killing cockroaches. Intake of this element causes stomach pains, vomiting and nausea, painful soles and palms of hands, limb weakness, double vision, involuntary eye movements, hallucina tions, characteristic hair loss and white lines across the nails. The symptoms are often mis-diagnosed as other diseases. Treatment is with the chemical Prussian Blue... 

State. When both iron environments contain only iron(II), the resulting salt is not colored (Prussian White). The oxidation state localization in PB has been studied extensively. Structures, electrochemical behavior (electrodes batteries), and uses in medicine (treatment of Cs and of thallium poisoning) of Prussian Blue are mentioned in a review of cyanide complexes. In cobalt-iron Prussian Blue analogues, NaxCo3,Fe(CN)6-zH20 electronic and spin states are controlled by temperature and the ligand field strength around the Co + ions, which in turn is determined by the Co Fe ratio. ... 

For acute exposure, ipecac should be administered and lavage performed. The use of single- or multiple-dose activated charcoal is supported by in vitro binding experiments and some animal data, and charcoal hemoperfusion may be a useful adjunct. Forced potassium diuresis appears to be harmful. Flemodial-ysis is also recommended with potassium administration. Since calcium metabolism is disturbed, supplementary calcium is indicated. The use of traditional metal chelators such as dimercaprol (British antilewisite) and penicillamine is not supported by the available evidence. In fact, the use of penicillamine may lead to redistribution of thallium into the central nervous system. Multiple animal studies have found evidence of enhanced elimination and improved survival with Prussian blue however, despite the fact that many humans have been treated with Prussian blue, the data presented are insufficient to judge its true efficacy. Despite this, one publication notes that... 

Prussian blue s safety profile is superior to that of other proposed therapies, and that it should be considered the drug of choice in acute thallium poisoning. 

Hoffman RS (2003) Thallium toxicity and the role of Prussian blue in therapy. Toxicology Review IT. 29-40. 

The FDA has approved the oral administration of Prussian Blue (ferric hexacy-anoferrate) to treat internal contamination with cesium and thallium (16). Prussian Blue works by increasing fecal excretion of these elements. Patients require treatment only if the exposure dose of Cs exceeds the annual limit (200 uCi from inhalation or 100 uCi from ingestion) (5). Clinicians should consult with a health physicist to determine whether exposure has exceeded the annual limit. Treatment for exposures between one and ten times the annual limit is controversial. However, exposures exceeding ten times the limit usually indicate the need for treatment. Once treatment has reduced the level of internal contamination below the annual limit, Prussian Blue treatment can stop. However, the clinician can use his or her discretion to discontinue treatment if residual levels remain above the annual limit after prolonged treatment (5). 

United States Food and Drug Administration, Center for Drug Evaluation and Research. Guidance for Industry on Prussian Blue for Treatment of Internal Contamination with Thallium or Radioactive Cesium, Avarlabrtity. Federal Register/Vol. 68, No. 23/Tuesday, February 4, 2003/Notices, http //www.fda.gov/OHRMS/DOCKETS/98fr/03-2597.pdf, last accessed 1-01-06... 

Prussian blue is a chelating agent. It insolubly binds radioactive and nonradioactive cesium and thallium in the GI tract by ion-exchange, adsorption, and mechanical trapping within the crystal structure. It is indicated in the treatment of patients with known or suspected internal contamination with radioactive cesium and/or radioactive or nonradioactive thallium to increase the rate of their elimination. 

Prussian Blue (Fe4[Fe(CN)j3) has become the therapy of choice, and has been proven effective in most accidental, suicidal, or criminal intoxications. Additional forced diuresis and prolonged hemodialysis results in good mobilization of thallium from the tissues (Pau 2000, Mizutani 2000, Atsmon et al. 2000). 

Hoeeman RS, Stringer JA, Feinberg RS and Golderank LR (1999) Comparative efficacy of thallium absorption by activated charcoal, Prussian blue, and sodium polystyrene sulfonate. Clin Toxicol 37 833-837. 

Rauws, A.G. (1974). Thallium pharmacokinetics and its modification by prussian blue. Arch. Pharmacol., 284, 295-306. 

Since the 1960s, Prussian blue has been used to treat people who have been internally contaminated with radioactive cesium (mainly Cs-137) or thallium (mainly Tl-201). Prussian blue can be given at any point after doctors have determined that a person is internally contaminated. Prussian blue will help speed up the removal of cesium and thallium from the body. 

Radioactive cesium and thallium, whether ingested or inhaled, will end up in the intestines. Prussian blue traps these materials in die intestines and keeps them from being absorbed by the body. The radioactive materials then move through the intestines and are excreted in bowel movements. Prussian blue reduces the biological half-life of cesium in the body from about 115 days to about 40 days. Prussian blue reduces the biological half-life of thallium from about 8 days to about 3 days. Because Prussian blue reduces the time that radioactive cesium and thallium stay in the body, it helps limit the amount of time the body is exposed to radiation. 

People SHOULD NOT take Prussian blue artist s dye in an attempt to treat themselves. This type of Prussian blue is not designed to treat radioactive contamination and is not manufactured in a germ-free area. People who are concerned about the possibility of being contaminated with radioactive cesium or thallium should go to their doctors for advice and treatment. 

---