Upon known exposure, usual therapy would involve Ca-DTPA or Zn-DTPA given in a 1-g dose as soon as possible. This may be given IV over 3–5 minutes in an undiluted form or may be diluted in 100–250 mL of normal saline, lactated Ringer's solution, or 5% dextrose in water. Administration time should not exceed 2 hours. Initial dose for pediatric patients is 14 mg/kg, not to exceed 1 g.
It is preferable to give Ca-DTPA for the initial dose because it is more effective than Zn-DTPA during the first 24 hours. After 24 hours, Zn-DTPA and CaDTPA are equally effective. If Ca-DTPA is not available or is contraindicated in a patient, the same dose of Zn-DTPA may be substituted. The FDA advises that Zn-DTPA is preferred for maintenance therapy because it is associated with smaller losses of essential minerals.
After the initial dose of Ca-DTPA, repeat doses of 1 g of Ca-DTPA or Zn-DTPA should be based on suspected level of internal contamination. Starting at the time of exposure, collect urine and fecal samples for bioassay to guide further treatment after the initial dose. The doses may be continued (usually 2–3 times per week) until the excretion rate of the transuranic is not increased by chelation administration (duration may vary from days to years). For long-term use, Ca-DTPA should be given with supplemental zinc therapy.
Intramuscular dosing generally is not recommended owing to ...