WARNINGS
Nebulized chelation therapy may be associated with exacerbation of asthma. Caution should be exercised when administering Zn-DTPA by the inhalation route. (See ADVERSE REACTIONS)
PRECAUTIONS
General
Treatment over several months with Zn-DTPA could lead to depletion of body stores of endogenous metals (e.g., magnesium, manganese). These elements should be monitored routinely and, if appropriate, mineral or vitamin plus mineral supplements should be provided.
Information for Patients
Radioactive metals are known to be excreted in the urine, feces, and breast milk. In individuals with recent internal contamination with plutonium, americium, or curium, Zn-DTPA treatment increases excretion of radioactivity in the urine. Appropriate safety measures should be taken to minimize contamination of others. When possible, a toilet should be used instead of a urinal, and it should be flushed several times after each use. Spilled urine or feces should be cleaned up completely and patients should wash their hands thoroughly. If blood or urine comes in contact with clothing or linens, they should be washed separately. Patients should drink plenty of fluids and void frequently. If patients are coughing, any expectorant should be disposed of carefully. Swallowing the expectorant should be avoided if possible. Parents and child-care givers should take extra precaution in handling the urine, feces, and expectorants of children to avoid any additional exposure to either the caregiver or to the child. Nursing mothers should take extra precaution in disposing of breast milk. (See PRECAUTIONS, Nursing Mothers)
Laboratory Tests
Serum electrolytes and essential metals should be closely monitored during Zn-DTPA treatment. Mineral or vitamin plus mineral supplements may be given as appropriate. (See PRECAUTIONS)
Drug-Drug Interactions
Adequate and well-controlled drug-drug interaction studies in humans were not identified in the literature. When an individual is contaminated with multiple radiocontaminants, or when the radiocontaminants are unknown, additional therapies may be needed (e.g., Prussian blue, potassium iodide).
Carcinogenesis, Mutagenesis, Impairment of Fertility
Studies with Zn-DTPA to evaluate carcinogenesis, mutagenesis and impairment of fertility have not been performed. Data for Zn-DTPA effects on spermatogenesis are not available.
Teratogenic Effects
Pregnancy Category B
There are no human pregnancy outcome data from which to assess the risk of Zn-DTPA exposure on fetal development. Reproduction studies have been performed in pregnant mice at doses up to 11.5 mmol/kg (31 times the recommended daily dose of 1 gram based on body surface area [BSA] adjusted dose) and have revealed no evidence of impaired fertility or harm to the fetus. There was a slight reduction in the average birth weight.
Treatment of pregnant women should begin and continue with Zn-DTPA. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed. The risk of toxicity from untreated internal radioactive contamination should be weighed against the risk of Zn-DTPA treatment.
Nursing Mothers
Studies to determine if Zn-DTPA is excreted in breast milk have not been conducted.
Radiocontaminants are known to be excreted in breast milk. Women with known or suspected internal contamination with radiocontaminants should not breast feed, whether or not they are receiving chelation therapy. Precautions should be taken when discarding breast milk. (See PRECAUTIONS, Information for Patients)
Pediatric Use
The safety and effectiveness of Zn-DTPA was established in the adult population and efficacy was extrapolated to the pediatric population for the intravenous route based on the comparability of pathophysiologic mechanisms. The dose is based on body size adjustment for an intravenous drug that is renally cleared. The safety and effectiveness of the nebulized route of administration has not been established in the pediatric population.
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