Chelation treatment is most effective if administered within the first 24 hours after internal contamination and should be started as soon as possible after suspected or known internal contamination. However, even when treatment cannot be started right away, individuals should be given chelation treatment as soon as it becomes available. Chelation treatment is still effective even after time has elapsed following internal contamination however, the chelating effects of Ca-DTPA (pentetate calcium trisodium inj) are greatest when radiocontaminants are still circulating or are in interstitial fluids. The effectiveness of chelation decreases with time following internal contamination as the radiocontaminants become sequestered in liver and bone. Individuals should drink plenty of fluids and void frequently to promote dilution of the radioactive chelate in the urine and minimize radiation exposure directly to the bladder. If internal contamination with radiocontaminants other than plutonium, americium, or curium, or unknown radiocontaminants is suspected, additional therapies may be needed (e.g., Prussian blue, potassium iodide). Initial Dose Adults and Adolescents: A single 1.0 gram initial dose of Ca-DTPA (pentetate calcium trisodium inj) administered intravenously. Pediatrics (less than 12 years of age): A single initial dose of 14 mg/kg administered intravenously not exceed 1.0 gram. Renally impaired patients: No dose adjustment is needed. However, renal impairment may reduce the rate at which chelators remove radiocontami-nants from the body. In heavily contaminated patients with renal impairment, dialysis may be used to increase the rate of elimination. High efficiency high flux dialysis is recommended. Because dialysis fluid will become radioactive, radiation precautions must be taken to protect personnel, other patients, and the general public. If Ca-DTPA (pentetate calcium trisodium inj) is not available, proceed with treatment with Zn-DTPA as initial therapy. Maintenance Treatment AFTER THE INITIAL DOSE, ON THE NEXT DAY, IF ADDITIONAL CHELATION THERAPY IS INDICATED, IT IS PREFERABLE TO SWITCH TO ZN-DTPA, IF AVAILABLE (SEE ZN-DTPA LABELING) DUE TO THE SAFETY CONCERNS ASSOCIATED WITH PROLONGED CA-DTPA (pentetate calcium trisodium inj) USE. IF ZN-DTPA IS NOT AVAILABLE, TREATMENT MAY CONTINUE WITH CA-DTPA (pentetate calcium trisodium inj) , HOWEVER MINERAL SUPPLEMENTS CONTAINING ZINC SHOULD BE GIVEN CONCOMITANTLY, AS APPROPRIATE. Adults and Adolescents: The recommended maintenance dose of Ca-DTPA (pentetate calcium trisodium inj) is 1.0 gram once a day administered intravenously. Pediatrics (less than 12 years of age): The recommended maintenance dose of Ca-DTPA (pentetate calcium trisodium inj) is 14 mg/kg once a day administered intravenously. The maximum daily dose should not exceed 1.0 gram per day. Renally impaired patients: No dose adjustment is needed. The duration of chelation treatment depends on the amount of internal contamination and individual response to treatment. (See Monitoring) Methods of Administration Intravenous administration of Ca-DTPA (pentetate calcium trisodium inj) is recommended and should be used if the route of internal contamination is not known or if multiple routes of internal contamination are likely. Ca-DTPA (pentetate calcium trisodium inj) solution (1 gram in 5 mL) should be administered either with a slow intravenous push over a period of 3-4 minutes or by intravenous infusion diluted in 100-250 mL of 5% dextrose in water (D5W), Ringers Lactate, or Normal Saline. In individuals whose internal contamination is only by inhalation within the preceding 24 hours, Ca-DTPA (pentetate calcium trisodium inj) can be administered by nebulized inhalation as an alternative route of administration. Ca-DTPA (pentetate calcium trisodium inj) should be diluted for neb-ulization at a 1:1 ratio with sterile water or saline. After nebulization, individuals should be encouraged to avoid swallowing any expectorant. Some individuals may experience respiratory adverse events after inhalation therapy. (See WARNINGS) The safety and effectiveness of the nebulized route of administration has not been established in the pediatric population. The safety and effectiveness of the intramuscular route of injection have not been established. (See OVERDOSE) Handling OPC ampoule: to open, turn so that the point faces upward and break off the neck with a downward movement. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. The product may be filtered using a sterile filter if particles are seen subsequent to opening of the ampoule. Monitoring When possible, obtain baseline blood and urine samples (CBC with differential, BUN, serum chemistries and electrolytes, urinalysis, and blood and urine radioassays) before initiating treatment. Ca-DTPA (pentetate calcium trisodium inj) must be given with very careful monitoring of serum zinc and complete blood counts. When appropriate, vitamin or mineral supplements that contain zinc should be administered. (See WARNINGS) To establish an elimination curve, a quantitative baseline estimate of the total internalized transuranium element(s) and measures of elimination of radioactivity should be obtained by appropriate whole-body counting, by bioassay (e.g., biodosimetry), or fecal/urine sample whenever possible. During Treatment
- Measure the radioactivity in blood, urine, and fecal samples weekly to monitor the radioactive contaminant elimination rate.
- Monitor CBC with differential, BUN, serum chemistries and electrolytes, and urinalysis regularly. If the individual is receiving more than one dose of Ca-DTPA (pentetate calcium trisodium inj) , these laboratory tests should be very carefully monitored and consider mineral supplementation as appropriate. (See CLINICAL PHARMACOLOGY, Pharmacodynamics, Adverse Metabolic Effects)
- Record any adverse events from Ca-DTPA (pentetate calcium trisodium inj) .