Prussian blue
RADIOGARDASE
What it isFerric hexacyanoferrate binding thallium and caesium in the gut; radiocaesium and thallium poisoning.
Why this oneIt interrupts enterohepatic recirculation, cutting the biological half-life of caesium by about two-thirds.
What limits itIt works only on what re-enters the gut, so it does not remove what is already fixed in tissue. Constipation; blue stools.
FDA label
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| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Internal contamination with radioactive cesium (137Cs) and/or thallium | Adults & adolescents | 3 g (6 capsules) TID (9 g/day) | ||
| Internal contamination with radioactive cesium (137Cs) and/or thallium | Pediatric 2–12y | 1 g (2 capsules) TID (3 g/day) |
Renal Undefined
Hepatic Not systemically bioavailable; may be less effective in hepatic impairment due to decreased biliary excretion of cesium/thallium
Instructions
- Initiate as soon as contamination is suspected; effective even when delayed — do not withhold
- Take with food to stimulate excretion of cesium or thallium
- If unable to swallow, open capsules and mix with bland food/liquid (may color oral mucosa and teeth blue)
- Anticipate treatment ≥30 days; base duration on weekly urine/fecal radioactivity and CBC/electrolyte monitoring
Available strengths
- cap 500 mg
Cautions
- Decreased GI motility can increase radiation absorbed dose to GI mucosa
- Constipation — monitor and treat
- Electrolyte abnormalities (hypokalemia) — monitor serum electrolytes
- Blue discoloration of feces, and of oral mucosa/dentition when capsules are opened
Adverse reactions
- Constipation (most common, ~24%)
- Hypokalemia
Pregnancy Category C; not absorbed from the GI tract, so fetal effects not expected — untreated cesium/thallium toxicity outweighs potential reproductive risk.
Lactation Excretion in milk unlikely (not absorbed), but women internally contaminated with cesium or thallium should not breastfeed.
Cost
| Strength | #/mo | generic $/mo | CostPlus | |
|---|---|---|---|---|
| 500 mg | cap | 90 TID | not offered |
NO BOXED WARNINGS
Principal riskIt works only on what re-enters the gut, so it does not remove what is already fixed in tissue
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilityConstipation and potassium/electrolyte depletion during prolonged treatment