Radiogardase® (Prussian Blue insoluble capsules) is a FDA-approved medical countermeasure for the treatment of known or suspected internal contamination with radioactive Cesium-137.

The 1987 radiological accident in Goiânia, Brazil serves as a stark warning of the dangers of Cesium-137. According to a report by the International Atomic Energy Agency (IAEA), the Goiânia accident started when scavengers took and dismantled a Cesium-137 teletherapy unit which Institute Goiâno de Radioterapia left at their old premises when they moved to a new one in 1985. Scraps of the unit were sold to a junkyard owner, who noticed that some of the materials glowed with a blue light in the dark. Mesmerized and enchanted by the light, friends and relatives of the junkyard owner received fragments of the material. Little they know that their fascination would snowball into one of the worst radiological incidents in the world: 112,000 person were monitored and at least 249 of whom were confirmed to be either internally or externally contaminated.

Due to the ubiquitous use of Cesium-137, there is a high risk of having radiological incidents involving it. It can be found in hospitals, factories, construction sites, and food processing plants. More worryingly, it can be used in weapons of terror, as the radioactive element in a “dirty bomb.”

Radiogardase® (Prussian blue insoluble capsules) is the only pharmaceutical countermeasure approved by the U.S. Food and Drug Administration as safe and effective for treating patients over the age of two years known or suspected to be internally contaminated with Cesium-137, radioactive Thallium-201, and non-radioactive Thallium.

The effectiveness of Radiogardase® was demonstrated in the 1987 Goiânia accident, the first extensive use of Prussian blue in the history of radiological accidents. Radiogardase® helps increase the excretion of Cesium-137 present in the digestive tract. However, patients exposed to radioactive elements in addition to Cesium-137 may require additional, concomitant treatment with other agents.

Also, Radiogardase® could be administered to rescue workers responding to suspected Cesium-137 events before they arrive on the scene. The anticipatory or immediate administration of Radiogardase® will not prevent first responders from becoming internally contaminated, but will ensure that the drug will be available to start working immediately if they became internally contaminated with Cesium-137.