Details About Overdose or Poisoning Generic Salt :: DTPA
Drug Pharmacology ::
I. Pharmacology. Diethylenetriaminepentaacetate(Zn-DTPA and Ca-DTPA) is a chelating agent that is used in a calcium orzinc salt form and functions by forming a chelate with metal ions(plutonium, americium, curium) that then can be excreted in urine. DTPAhas a plasma half-life of 20–60 minutes and is distributed in theextracellular space. It has a small amount of protein binding and doesnot undergo significant metabolism or tissue accumulation. The use ofCa-DTPA within one hour of contamination resulted in a 10-fold higherrate of elimination of plutonium compared with Zn-DTPA. Ca-DTPA is moreeffective than Zn-DTPA when given within 24 hours after internalcontamination.
Drug Indications ::
Indications. DTPAis FDA indicated for internal contamination with plutonium, americium,and curium. It has also been used for treatment of internalcontamination with californium and berkelium.
Drug Contra-Indications ::
Known hypersensitivity to the agent.
DTPA should not be used in uranium or neptunium exposures as it may increase bone deposition of these elements.
Ca-DTPA should not be used in patients with renal failure, nephrotic syndrome, or bone marrow suppression.
Drug Adverse Effects ::
IV. Adverse effects
Nausea, vomiting, and diarrhea.
Fever, chills and myalgias.
Life-threateningside effects are distinctly uncommon, with no serious toxicity in humansubjects after 4500 administrations of Ca-DTPA and 1000 administrationsof Zn-DTPA.
Use in pregnancy. FDAcategory C (Ca-DTPA) and category B (Zn-DTPA); Zn-DTPA may be used inpregnancy, though fetal risks are not completely known (see TableIII–1).
Drug Lab Interactions ::
Drug or laboratory interactions
There are no major known drug interactions.
There does not appear to be a decrement of body trace elements associated with the use of DTPA.
Drug Dose Management ::
Dosage and method of administration
Uponknown exposure, usual therapy would involve Ca- or Zn-DTPA given in a1-g dosage as soon as possible. This may be given IV over 3–5 minutesin an undiluted form or may be diluted in 100–250 cc of NS, LR, 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 since it is moreeffective than Zn-DTPA during the first 24 hours. After 24 hours,Zn-DTPA and Ca-DTPA are equally effective. If Ca-DTPA is not availableor is contraindicated in a patient, the same dose of Zn-DTPA may besubstituted.
C. Afterthe initial dose of Ca-DTPA, treatment with 1 g of Zn-DTPA daily shouldbe continued. If Zn-DTPA is not available, maintenance treatment can becontinued with Ca-DTPA along with mineral supplements containing zincif necessary. Treatment may be continued for days, months, or yearsdepending on body burden and individual response to therapy. Generallygiven until the excretion enhancement factor (EEF) approaches 1.
IM dosing generally is not recommended owing to significant pain with injection.
E. Pregnant women should only be treated with Zn-DTPA.
F.Nebulization in a 1:1 dilution is safe and effective for persons onlycontaminated only via inhalation. The intravenous route should be usedif multiple routes of internal contamination occurred or the route isunknown.
Drug Chemical Formulations ::
Parenteral or nebulization.Pentetate Calcium Trisodium Injection (Ca-DTPA); Pentetate ZincTrisodium Injection (Zn-DTPA). One gram in 5 cc of diluent (200 mg/cc)packaged in single-use clear glass ampules. This is provided in boxesof 10 ampules for each salt (Ca-DTPA and Zn-DTPA) by Akorn Inc.
The suggested minimum stocking levelto treat a 70-kg adult for the first 24 hours is one ampule (1 gram) ofDTPA. It is advisable to stock both Ca-DTPA and Zn-DTPA. DTPA is keptin the Strategic National Stockpile (SNS) at the CDC. TheRadiation Emergency Assistance Center (REAC/TS), can be contacted forinformation on obtaining DTPA and its recommended dosing (576-3131, on the Internet at www.orau.gov/reacts).