calciumDTPA

Calcium diethylenetriaminepentaacetate, or calcium DTPA, is the calcium salt of diethylenetriaminepentaacetate, a polyvalent chelating agent. DTPA binds a range of metal ions, and its calcium salt is used medically to form soluble complexes with certain radionuclides, aiding their removal from the body through urine.

Calcium DTPA is used as a decorporation agent after internal contamination with certain radioactive elements, particularly actinides such as plutonium, americium, and curium. When administered after exposure, it enhances the excretion of these radionuclides and can reduce total body burden, especially if given promptly under medical supervision. It is typically part of an emergency response protocol rather than a general antidote.

Administration and safety considerations: Ca-DTPA is usually given by injection, either intravenously or intramuscularly, with dosing and duration customized to the individual’s age, exposure type, and time since intake. Regimens may involve repeated doses over several days. Side effects can include injection-site reactions, flushing, nausea, and electrolyte disturbances due to chelation of essential minerals. Because it can affect levels of essential metals, treatment requires close monitoring and is conducted under specialist supervision as part of a comprehensive radiological incident response.

Relation to other chelators: Zinc DTPA (Zn-DTPA) is another chelating agent used for decorporation and is selected based on clinical factors such as age and potential mineral depletion. In practice, the choice between calcium and zinc DTPA depends on the exposure scenario and patient characteristics.

Regulatory status: Ca-DTPA is stockpiled and deployed in radiological emergency plans in several countries and issued under medical guidelines for appropriate use.