RADIOGARDASE (PRUSSIAN BLUE)
Clinical safety rating: caution
Comprehensive clinical and safety monograph for RADIOGARDASE (PRUSSIAN BLUE) (RADIOGARDASE (PRUSSIAN BLUE)).
Prussian blue acts as an ion-exchange resin that binds cesium and thallium ions in the gastrointestinal tract, interrupting enterohepatic circulation and enhancing fecal excretion of these radioactive isotopes, thereby reducing their systemic absorption and retention.
| Metabolism | Prussian blue is not metabolized and is excreted unchanged in feces. |
| Excretion | Primarily fecal (>99%) via biliary excretion of unabsorbed drug and bound cesium/ thallium complexes. Renal excretion is negligible (<0.5%). |
| Half-life | For cesium-137 elimination: 50–110 days (mean ~80 days) in adults; half-life of Prussian blue itself is not clinically relevant as it is not absorbed. |
| Protein binding | Negligible; Prussian blue is a crystal lattice with no significant binding to plasma proteins. |
| Volume of Distribution | Essentially 0 L/kg as the drug is not absorbed; remains confined to the intestinal lumen. |
| Bioavailability | Not applicable; Prussian blue is not absorbed (oral bioavailability <0.1%). |
| Onset of Action | Oral: Binds cesium/thallium in the gut within 1–2 hours; clinical effect on reducing radioisotope whole-body retention begins within 24 hours. |
| Duration of Action | Duration of binding effect persists as long as the drug remains in the GI tract (transit time ~12–48 hours). Repeated dosing maintains continuous binding throughout treatment (30 days for cesium, variable for thallium). |
3 g (as 1 g capsules, 3 capsules) orally three times daily for a minimum of 30 days.
| Dosage form | CAPSULE |
| Renal impairment | No dose adjustment required for renal impairment; drug is minimally absorbed and renally excreted unchanged. |
| Liver impairment | No dose adjustment required for hepatic impairment; drug is not hepatically metabolized. |
| Pediatric use | Children 2-12 years: 1 g orally three times daily. Infants and toddlers: consult specialist. |
| Geriatric use | No specific dose adjustment; use standard adult dosing with monitoring for constipation and electrolyte disturbances. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for RADIOGARDASE (PRUSSIAN BLUE) (RADIOGARDASE (PRUSSIAN BLUE)).
| Breastfeeding | Prussian blue is not absorbed systemically and is unlikely to pass into breast milk. However, it is recommended to avoid breastfeeding during treatment due to potential excretion of radioactive contaminants into milk. M/P ratio is not applicable due to negligible absorption. |
| Teratogenic Risk | Prussian blue is considered to have low teratogenic risk due to its insolubility and lack of systemic absorption. Animal studies have not shown fetal harm, and there are no well-controlled human studies. Use during pregnancy is justified for life-threatening radioactive contamination, weighing risks versus benefits. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to Prussian blue or any component of the formulation","Gastrointestinal obstruction"]
| Precautions | ["Use caution in patients with gastrointestinal motility disorders or obstruction","May cause constipation, requiring laxatives to enhance elimination","May discolor stool and mouth (blue/green)","Monitor serum potassium and magnesium levels as interference with electrolytes may occur","Use in pregnancy only if clearly needed; limited data available"] |
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| Fetal Monitoring | Monitor maternal and fetal radiation exposure levels if applicable. Assess for gastrointestinal adverse effects in the mother, such as constipation. No specific fetal monitoring required beyond standard obstetric care. |
| Fertility Effects | No known effects on fertility based on nonclinical studies. Prussian blue is not absorbed, thus unlikely to impact reproductive organs or hormones. |