AN-DTPA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for AN-DTPA (AN-DTPA).
AN-DTPA (pentetate calcium trisodium) is a chelating agent that binds to and removes heavy metals, such as plutonium, americium, curium, and other transuranic elements, from the body. It forms stable complexes with these metals, which are then excreted via the kidneys.
| Metabolism | AN-DTPA is not metabolized. It is rapidly distributed in extracellular fluid and eliminated unchanged by glomerular filtration. |
| Excretion | Renal: >95% as unchanged drug via glomerular filtration. Biliary/fecal: <5%. |
| Half-life | Terminal elimination half-life: approximately 1.5-2 hours in patients with normal renal function. Extended significantly in renal impairment (up to 24 hours in anuria). |
| Protein binding | Essentially none (<1%). |
| Volume of Distribution | Vd: approximately 0.3-0.4 L/kg, indicating distribution primarily in extracellular fluid and minimal tissue binding. |
| Bioavailability | Intravenous: 100%. Oral: negligible (<1%) due to poor gastrointestinal absorption. |
| Onset of Action | Intravenous: immediate (within 1-2 minutes). |
| Duration of Action | Intravenous: duration of chelation effect approximately 1-2 hours, with urinary excretion of chelated radionuclides occurring over 6-24 hours. |
1 gram by intravenous injection or infusion daily for 5 consecutive days, starting immediately after the end of radiotherapy.
| Dosage form | INJECTABLE |
| Renal impairment | No specific guidelines; use with caution in severe renal impairment (CrCl <30 mL/min) due to potential toxicity. |
| Liver impairment | No specific guidelines; use standard dosing with monitoring of liver function tests. |
| Pediatric use | Not established for use in children; safety and efficacy not determined. |
| Geriatric use | Elderly patients may be more sensitive to the effects; use standard adult dosing with close monitoring for toxicity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for AN-DTPA (AN-DTPA).
| Breastfeeding | No human data on AN-DTPA excretion in breast milk. Due to potential toxicity, breastfeeding is not recommended during therapy. M/P ratio unknown. |
| Teratogenic Risk | AN-DTPA is a chelating agent not recommended during pregnancy. Animal studies suggest potential teratogenicity at high doses. First trimester: increased risk of congenital anomalies. Second/third trimester: fetal toxicity including skeletal abnormalities. Contraindicated unless clearly needed. |
| Fetal Monitoring |
■ FDA Black Box Warning
WARNING: AN-DTPA can cause severe, life-threatening anaphylactic reactions and immune-mediated reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis. Patients with known hypersensitivity to DTPA or any component of the formulation should not receive this drug. Resuscitation equipment and personnel trained in managing anaphylaxis must be immediately available during administration.
| Serious Effects |
Absolute: Known hypersensitivity to DTPA or any component; severe renal impairment (unless benefit outweighs risk). Relative: Pregnancy (use only if potential benefit justifies risk to fetus; gadolinium-based contrast agents have been associated with adverse outcomes); breastfeeding (discontinue nursing or the drug, considering importance to mother).
| Precautions | May cause nephrotoxicity, especially in patients with preexisting renal impairment; monitor renal function closely. Hypocalcemia may occur due to chelation of calcium; monitor serum calcium levels. Anaphylactic and other hypersensitivity reactions have been reported. Use with caution in patients with asthma or history of allergic reactions. May cause depletion of essential trace metals (e.g., zinc, magnesium) with prolonged use; consider supplementation. |
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| Monitor maternal renal function, electrolyte levels, and hematologic parameters. Fetal monitoring with ultrasound for skeletal development if exposure occurs. |
| Fertility Effects | Animal studies show no significant effects on fertility. Human data insufficient; potential for transient hormonal disturbances. |
| Food/Dietary |
| No specific food interactions with AN-DTPA. However, patients should be well-hydrated; avoid caffeine and alcohol on the day of the scan as they may affect renal function and hydration status. No dietary restrictions required. |
| Clinical Pearls | AN-DTPA is a radiopharmaceutical (technetium-99m pentetate) used for renal scintigraphy. It is cleared by glomerular filtration, making it ideal for evaluating renal function and obstruction. Ensure adequate hydration to improve image quality. Note that a rising or flat renogram curve post-diuretic suggests obstruction. In pediatric patients, reduce dose based on weight per institutional protocols. Always confirm pregnancy status in women of childbearing age. |
| Patient Advice | You are receiving a radioactive tracer for a kidney scan; the amount of radiation is minimal and safe. · Drink plenty of water before and after the scan to help the tracer clear through your kidneys. · You may be given a diuretic (water pill) during the test to assess for blockage; this is normal. · The injection may cause brief discomfort at the site; the scan itself is painless. · Report any allergic reactions like rash or difficulty breathing immediately. · Inform the technologist if you are pregnant, breastfeeding, or have any kidney problems. |