Dtpa Series

“Ca-DTPA and Zn-DTPA should not be administered simultaneously.

FDA recommends that, if both products are available, Ca-DTPA be given as the first dose.

• If additional treatment is needed, treatment should be switched to Zn-DTPA. This treatment sequence is recommended because Ca-DTPA is more effective than Zn-DTPA during the first 24 hours after internal contamination.
• After the initial 24 hours, Zn-DTPA and Ca-DTPA are similarly effective, but Ca-DTPA causes more loss of essential metals, such as zinc, from the body. Therefore, Zn-DTPA is preferred for maintenance therapy.
• If Ca-DTPA is not available or treatment cannot be started within the first 24 hours after contamination, treatment should begin with Zn-DTPA.
• If Zn-DTPA is not available, Ca-DTPA can be given for continued treatment, along with vitamin or mineral supplements that contain zinc.

Ca-DTPA and Zn-DTPA can be administered by nebulizer or directly into the blood stream (i.e. intravenously).

• If the route of internal contamination is through inhalation alone, then nebulized chelation therapy will suffice.
• If the routes of contamination are multiple (e.g., inhalation and through wounds), then intravenous chelation therapy is preferred.

The duration of treatment is dictated by the level of internal contamination and the individual’s response to therapy.

• Levels of internal contamination should be ascertained weekly during chelation therapy to determine when to terminate treatment.

Zn-DTPA is the preferred treatment for the pregnant woman with internal contamination.

• According to the Ca-DTPA FDA drug label: "Based on animal data, Ca-DTPA may cause fetal harm. Chelation treatment of pregnant women should begin and continue with Zn-DTPA. If Zn-DTPA is not available, Ca-DTPA should be used."

In most cases of contamination with transuranium elements, it is unlikely that immediate illness would occur.

In order to reduce the risks of future biological effects, Ca-DTPA or Zn-DTPA should be taken as soon as possible after internal contamination, following or concurrent with distancing the individual from the radioactive source and appropriate external decontamination.

However, even when treatment cannot be started right away, individuals should be given Ca-DTPA or Zn-DTPA as soon as the products are available.

Treatment with Ca-DTPA or Zn-DTPA is still effective even after time has elapsed since contamination, but effectiveness decreases once these elements are trapped in the bones.”