DTPA (Diethylenetriamine Pentaacetic Acid)
Pentetate calcium trisodium / Pentetate zinc trisodium
Brand names:Ca-DTPA, Zn-DTPA
A chelating agent used to bind and accelerate the elimination of transuranic radioactive metals (plutonium, americium, curium) from the body following internal radiological contamination. DTPA does not protect against external radiation or against radioactive iodine (potassium iodide is the antidote for iodine isotopes). Two formulations exist: Ca-DTPA for initial treatment, Zn-DTPA for extended treatment.
Pharmacology and Actions
DTPA is a polyamino acid that forms stable water-soluble chelates with transuranic and rare-earth metals. The chelate is excreted in urine, removing the radioactive material from the body. Ca-DTPA has higher chelation efficiency for the first 24 hours after exposure due to its higher affinity for the target metals and willingness to exchange the calcium ion. Zn-DTPA has comparable affinity but better safety profile for repeated dosing because zinc replacement does not produce the trace metal depletion that prolonged Ca-DTPA can cause.
Indications
- Internal contamination with plutonium (Pu-238, Pu-239, Pu-241)
- Internal contamination with americium (Am-241)
- Internal contamination with curium (Cm-242, Cm-244)
- Internal contamination with other transuranic radionuclides confirmed or suspected to be amenable to DTPA chelation
Absolute Contraindications
- Pregnancy (relative contraindication; risk versus benefit assessment required given radiological exposure context)
- Severe renal impairment (relative contraindication; reduced clearance of DTPA-metal complex)
- No absolute contraindications in confirmed transuranic contamination
Precautions and Side Effects
Generally well tolerated. Mild reactions: nausea, vomiting, diarrhea, chills, fever, pruritus, muscle cramps. Trace metal depletion (zinc, manganese, magnesium) with prolonged Ca-DTPA use; transition to Zn-DTPA after first 24 hours to minimize. Hypersensitivity reactions rare. Not effective for uranium (use bicarbonate) or radioactive iodine (use potassium iodide).
Adult Dosing
Pediatric Dosing
Under 12 years: 14 mg/kg IV (max 1 g) daily. Adolescent over 12 years: adult dose. Nebulized dosing 14 mg/kg in sterile water, max 1 g.
Pharmacokinetics
Peak Effect: Chelation peaks within first 24 hours of administration
Duration: Plasma half-life approximately 90 minutes; chelation effect over 24 hours per dose
Storage and Handling
Room temperature 15 to 30 degrees C. Ca-DTPA and Zn-DTPA supplied as 1 g vials of solution (200 mg/mL). Shelf life typically 5 years. Strategic National Stockpile maintains rotating inventory through extended shelf life programs.
Reconstitution:
Pre-mixed 1 g/5 mL solution; ready to use IV or for nebulization. Dilute in 100 to 250 mL D5W or NS for slower IV infusion if desired. For nebulization: dilute 1 g in 5 mL sterile water or saline.
TCCC and TECC Role
Not a TCCC trauma medication. Component of CBRN response and Strategic National Stockpile for radiological incident response. Administered by toxicology-trained providers or under guidance from REAC/TS (Radiation Emergency Assistance Center/Training Site) or state radiation health authorities. FEMA and HHS coordinate stockpile deployment for incidents requiring DTPA.
DTPA is the antidote for the high-consequence end of CBRN events: dirty bomb dispersal of plutonium or americium, nuclear weapon detonation aftermath, or industrial accident at a transuranic processing facility. It is not relevant to most radiological exposures (radioactive iodine uses KI, uranium uses bicarbonate, cesium uses Prussian blue). The timing window matters operationally: DTPA is most effective when given within hours of internal contamination, before the radionuclide is incorporated into bone and other long-term reservoirs. Decision to administer requires confirmation or strong suspicion of transuranic exposure, which typically comes from radiation monitoring at the incident scene and consultation with radiation medicine specialists. Carrying DTPA forward of role 2 is operationally unusual but appropriate for tactical units operating in known transuranic risk environments.
Using DTPA for radiation exposures it does not address. DTPA does not protect against external radiation, does not chelate radioactive iodine (use KI), does not bind uranium (use sodium bicarbonate to alkalinize urine), and does not bind cesium (use Prussian blue / Radiogardase). Always confirm the radionuclide before administering DTPA. The other common mistake is delaying administration while awaiting confirmation; for high-suspicion transuranic exposure, REAC/TS guidance supports empiric administration within hours of exposure.
This drug profile is provided as educational reference material for trained medical providers. It is not medical advice, not a substitute for formal training, and not a substitute for current published guidelines or medical direction.
Drug administration is governed by your scope of practice, agency standing orders, medical director protocols, and applicable state and federal regulations. Controlled substances are subject to additional handling, accountability, and documentation requirements per DEA and state law. Always verify dosing, indications, contraindications, and route of administration against current published guidelines and your local protocols before administration.
If this content is being viewed during a medical emergency, call 911 immediately and follow the direction of your local emergency dispatch and medical control. Do not use this reference as a substitute for emergency medical services.
Drug information evolves. Last reviewed dates and source citations are provided for each entry. Confirm currency against the cited source before clinical use.
Penn Tactical Solutions publishes this reference for educational purposes. PTS does not provide medical direction and does not assume responsibility for clinical decisions made in the field. Clinical responsibility rests with the administering provider, their medical director, and their agency.
Educational reference for trained medical providers. Not medical advice. Not a substitute for formal training, current published guidelines, or medical direction. Drug administration is governed by your scope of practice, agency standing orders, medical director protocols, and applicable state and federal regulations. Controlled substances require additional storage, accountability, and documentation per DEA and state law.
In a medical emergency, call 911. This reference is not a substitute for emergency medical services.
Verify dosing, indications, and contraindications against current published guidelines and your local protocols before administration. Confirm content currency against the source citation. Penn Tactical Solutions does not provide medical direction. Clinical responsibility rests with the administering provider, their medical director, and their agency.
DTPA (Diethylenetriamine Pentaacetic Acid)
| IV/IO | 1 g IV slow push over 3 to 4 minutes, or infused in 100 to 250 mL D5W or NS over 30 minutes. Daily dosing for 5 days typical; longer courses possible based on continued urinary excretion of chelated metal. Switch from Ca-DTPA to Zn-DTPA after first 24 hours for extended treatment. (Chelation begins within minutes; urinary excretion of chelated metal evident within hours) |
| IM | Not preferred (use IV or nebulizer) (None) |
| IN | Nebulized: 1 g DTPA in 5 mL sterile water or saline, nebulized over 10 to 15 minutes. Useful for inhalation exposure (transuranic dust inhalation) to deliver chelation directly to pulmonary deposit. (Within minutes for inhaled contamination) |
| PO | Not absorbed orally; not used PO (None) |