Prussian Blue (Monograph)

Brand name: Radiogardase
Drug class: Other Ion-removing Agents
VA class: AD900
Chemical name: Ferric hexacyanoferrate (II)
Molecular formula: Fe₄[Fe(CN)₆]₃
CAS number: 14038-43-8

Medically reviewed by Drugs.com on Aug 22, 2023. Written by ASHP.

Introduction

A crystal lattice of ferric hexacyanoferrate (II); an ion-exchange medium with high affinity for cesium and thallium, including radioactive isotopes of these metals.

Uses for Prussian Blue

Poisoning and Radioactive Exposure

Treatment of known or suspected internal contamination with radioactive cesium and/or radioactive or nonradioactive thallium following accidental exposure and/or intentional exposure from radioactive terrorism or warfare. Reduces the risk of death and major morbidity following exposure to these metals.

Treatment of radioactive exposures when the nature of the radioactive contamination is unknown.

For severe thallium intoxication, may need to employ additional measures (e.g., induction of emesis followed by gastric intubation and lavage, forced diuresis, charcoal hemoperfusion, hemodialysis) to enhance thallium elimination.

Prussian Blue Dosage and Administration

General

• Initiate therapy as soon as possible after contamination is suspected.

• Cesium poisoning: Determine baseline internalized¹³⁷Cs contamination (by whole-body counting, bioassay, or urine/feces sampling) if possible. Measure radioactivity counts in urine and feces weekly to monitor¹³⁷Cs elimination rate. Assess whole-body radioactivity after 30 days of therapy.

• Thallium poisoning: Determine baseline internalized thallium contamination (by whole-body counting and/or bioassay) if possible. Monitor CBC and serum chemistry and electrolytes weekly during therapy.

Administration

Oral Administration

Administer orally with food to stimulate excretion of cesium or thallium.

If patients cannot tolerate swallowing large numbers of capsules, open the capsules and mix the contents with bland food or liquids.

Use with appropriate measures (i.e., oral fiber-based laxatives and/or a high-fiber diet) to promote regular fecal elimination.

Can be given with 15% mannitol to prevent constipation.

Dosage

Pediatric Patients

Poisoning and Radioactive Exposure

Cesium Poisoning

Oral

Children 2–12 years of age: 1 g 3 times daily.

Children ≥13 years of age: 3 g 3 times daily. Once internal radiation has decreased substantially, reduce dosage to 1 or 2 g 3 times daily (to improve GI tolerance).

Continue for a minimum of 30 days. Duration of therapy based on level of contamination and clinical judgment.

Thallium Poisoning

Oral

Children 2–12 years of age: 1 g 3 times daily.

Children ≥13 years of age: 3 g 3 times daily.

Duration of therapy based on level of contamination and clinical judgment.

Adults

Poisoning and Radioactive Exposure

Cesium Poisoning

Oral

3 g 3 times daily. Once internal radiation has decreased substantially, reduce dosage to 1 or 2 g 3 times daily (to improve GI tolerance).

Continue for a minimum of 30 days. Duration of therapy based on level of contamination and clinical judgment.

Thallium Poisoning

Oral

3 g 3 times daily.

Duration of therapy based on level of contamination and clinical judgment.

Special Populations

No special population dosage recommendations at this time.

Related/similar drugs

potassium iodide, Iosat, AN-DTPA, Pima

Cautions for Prussian Blue

Contraindications

• No contraindications according to manufacturer.

Warnings/Precautions

Warnings

Radiation Exposure

Effective only in decreasing radiation exposure; does not treat complications of such exposure. Provide supportive treatment for radiation toxicity (e.g., for severe neutropenia and thrombocytopenia) in conjunction with prussian blue therapy.

In radiologic emergencies, the type of elemental exposure may not be known. Prussian blue may not bind to all radioactive elements; therefore, may need to use other radioprotectants (e.g., potassium iodide, edetate calcium disodium, sodium alginate) in addition to prussian blue in patients contaminated with unknown or multiple radioactive elements.

Major Toxicities

GI Effects

Constipation reported frequently; constipation responds to oral administration of fiber (i.e., fiber-based laxatives and/or a high-fiber diet).

Decreased GI motility will slow the GI transit time of the prussian blue-metal complex (i.e., prussian blue-¹³⁷Cs, prussian blue-thallium) and may increase exposure to the metal. Caution in individuals with conditions associated with decreased GI motility.

General Precautions

Hypokalemia

Hypokalemia (serum potassium concentrations of 2.5–2.9 mEq/L) reported. Closely monitor serum electrolytes.

Use with caution in individuals with preexisting cardiac arrhythmias or electrolyte imbalances.

Specific Populations

Pregnancy

Category C.

Lactation

Prussian blue is unlikely to distribute into breast milk.

Cesium and thallium are distributed into human breast milk; women contaminated with these metals should not breast-feed.

Pediatric Use

Safety and efficacy and dosage recommendations in pediatric patients ≥2 years of age extrapolated from adult data and supported by experience in pediatric patients (4–12 years of age).

Dosing recommendations not established for pediatric patients <2 years of age.

Hepatic Impairment

Use not contraindicated; however, may be less effective in these patients due to decreased excretion of cesium and/or thallium in the bile.

Renal Impairment

Use not contraindicated.

Common Adverse Effects

Constipation, GI distress, blue discoloration of sweat and tears (long-term administration).

Drug Interactions

Orally Administered Drugs and Nutrients

Possible pharmacokinetic interaction (binding of prussian blue to drug and/or essential nutrient). Monitor serum concentrations and/or clinical response in patients receiving clinically important drugs.

Specific Drugs

Prussian Blue Pharmacokinetics

Absorption

Bioavailability

Not appreciably absorbed through intact GI wall.

Elimination

Elimination Route

Eliminated unchanged in feces. Clearance depends on GI transit time.

Stability

Storage

Oral

Capsules

In the dark at 25°C (may be exposed to 15–30°C).

Actions

• An ion-exchange medium with high affinity for cesium and thallium, including radioactive isotopes of these metals.

• Binds cesium and/or thallium in the GI tract, thus preventing absorption or reabsorption of these metals and increasing the rate of their elimination as insoluble complexes in feces.

• Reduces whole-body effective half-life of cesium and mean serum biologic half-life of thallium.

• May bind other elements (e.g., potassium). (See Hypokalemia under Cautions.)

• Importance of taking prussian blue with food; importance of taking appropriate measures (i.e., oral fiber-based laxatives and/or a high-fiber diet) to promote regular fecal elimination.

• Importance of instructing patients on safety measures that should be used to minimize radiation exposure to others, including appropriate disposal of urine and feces. Clothing contaminated with blood or urine should be washed separately.

• Advise patients of possible bluish appearance of their stools.

• Advise patients who are unable to swallow capsules that their mouth and teeth might be colored blue if prussian blue capsules are opened and the contents mixed with food or liquid.

• Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.

• Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs.

• Importance of informing patients of other important precautionary information. (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

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Frequently asked questions

• My stool has changed color. What does it mean?

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