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Prussian blue insoluble is administered to decrease radiation exposure. It does not treat the complications of radiation exposure. Patients contaminated with high doses of 137Cs 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 137Cs 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.
Prussian blue insoluble may bind electrolytes found in the gastrointestinal tract. Asymptomatic hypokalemia, with serum potassium values of 2.5 – 2.9 (normal 3.5 – 5.0), was reported in 3/42 (7%) of patients on treatment with Prussian blue insoluble. Serum electrolytes should be closely monitored during Prussian blue insoluble treatment. Caution should be exercised when treating patients with pre-existing cardiac arrhythmias or electrolyte imbalances.
Prussian blue insoluble may bind some orally administered therapeutic drugs. As appropriate, blood levels or clinical response to oral medications should be monitored.
Carcinogenesis, Mutagenesis, Impairment of Fertility
Studies with Prussian blue insoluble to evaluate carcinogenesis, mutagenesis and impairment of fertility have not been performed.
Pregnancy Category C
Comprehensive animal reproductive studies have not been conducted with Prussian blue insoluble. Since Prussian blue insoluble is not absorbed from the gastrointestinal tract, effects on the fetus are not expected. In one patient that became pregnant 3 years and 8 months after being treated with Prussian blue insoluble for internal contamination with 137Cs (8 mCi), complications or birth defects were not identified in the literature report.
Cesium-137 is known to cross the human placenta. One patient, in Goiânia, was contaminated with 0.005 mCi 137Cs during her 4th month of pregnancy. She was not treated with Prussian blue insoluble. At birth the concentration of 137Cs was the same in the mother and the infant. Thallium crosses the human placenta. Reported fetal effects in the reviewed literature include fetal death, failure to thrive, alopecia, or in some instances outwardly normal development. The risk of toxicity from untreated radioactive cesium or thallium exposure is expected to be greater than the reproductive toxicity risk of Prussian blue insoluble.
Studies to determine if Prussian blue insoluble is excreted in human milk have not been conducted. Since Prussian blue insoluble is not absorbed from the gastrointestinal tract, its excretion in milk is highly unlikely. However, cesium and thallium are transmitted from mother to infant in breast milk. Women internally contaminated with cesium or thallium should not breast feed.
The safety and efficacy of Prussian blue insoluble and its dosing for the pediatric population was extrapolated from adult data and supported by pediatric patients who were internally contaminated with 137Cs and treated with Prussian blue insoluble in the Goiânia accident.
Overall, 27 pediatric patients received Prussian blue insoluble in the range of 3 – 10 grams per day in divided doses. Prussian blue insoluble treatment reduced the whole body effective halflife of 137Cs by 46% in adolescents and by 43% in children aged 4 to 12 years of age. In 12 patients for whom the rate of radiation elimination data are available, the rate was similar to that in adults treated with 3 grams TID and in pediatric patients treated with 1 gram TID. (See CLINICAL PHARMACOLOGY, Clinical Trials, Table 2.) By body weight, the dose ranged from 0.32 gram/kg in the 12-year old patient (10 gram Prussian blue daily dose, 31 kg weight) to 0.21 gram/kg in the 4 year old patient (3 gram Prussian blue daily dose, 14 kg weight).
Pediatric patients aged 2 up to 4 years are expected to have biliary and gastrointestinal function that is comparable to a 4-year old.
There are variations in the developmental maturity of the biliary system and gastrointestinal tract of neonates and infants (0 – 2 years). The dose-related adverse effects of Prussian blue insoluble on an immature gastrointestinal tract are not known. Dosing in infants and neonates has not been established.This monograph has been modified to include the generic and brand name in many instances.
Last reviewed on RxList: 10/1/2008
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