Edetate Calcium Disodium

Chelating Agent Heavy Metal Antagonist

Dosage & Administration Guidelines

Species Route Dose Frequency Duration & Clinical Notes
Dog IV (slow infusion) or SC (diluted) 100 mg/kg/day (total daily dose) divided into 2-4 doses; or 25 mg/kg q6h q6h to q12h Duration: 3-5 days, then 2-4 days off, repeat as needed
Notes: Administer as a 0.5-1% solution in 5% dextrose or saline. Monitor renal function and hydration.
Cat IV (slow infusion) or SC (diluted) 25 mg/kg q6h or 100 mg/kg/day divided q6h Duration: 3-5 days, then 2-4 days off, repeat as needed
Notes: Use with caution in cats; monitor for renal toxicity.
Horse IV 75 mg/kg/day divided q8-12h q8-12h Duration: 3-5 days
Notes: Limited data; use with supportive care.
Cattle IV 110 mg/kg/day divided q12h q12h Duration: 3-5 days
Notes: Not commonly used; withdrawal times must be observed.
Small Ruminants IV 110 mg/kg/day divided q12h q12h Duration: 3-5 days
Notes: Limited data; use with caution.
Rabbit SC or IV 25-50 mg/kg q12h q12h Duration: 3-5 days
Notes: Use with supportive care; monitor renal function.
Birds/Poultry IM or IV 25-50 mg/kg q12h q12h Duration: 3-5 days
Notes: Limited data; use with caution.

Clinical Indications & Species Uses

General Indications
  • Chelation therapy for heavy metal poisoning, primarily lead
Dog (Canine)
  • Lead poisoning
  • Zinc toxicosis (as adjunctive therapy)
  • Copper toxicosis (in some cases)
Cat (Feline)
  • Lead poisoning
  • Zinc toxicosis (as adjunctive therapy)
Horse (Equine)
  • Lead poisoning (rarely used)
Cattle (Bovine)
  • Lead poisoning (rarely used)
Small Ruminants (Sheep / Goat)
  • Lead poisoning (rarely used)
Rabbit & Small Mammals
  • Lead poisoning (rarely used)
Avian & Poultry
  • Lead poisoning (rarely used)
Exotic & Other Species
  • Lead poisoning in exotic species (rarely used)

Pharmacology & Mechanism of Action

Drug Class: Chelating Agent | Pharmacological Group: Heavy Metal Antagonist

Mechanism of Action: Edetate calcium disodium (calcium disodium EDTA) chelates divalent and trivalent heavy metals, forming stable, soluble complexes that are excreted in the urine. The calcium in the molecule is displaced by lead (and other metals with higher affinity for EDTA), resulting in a non-toxic lead-EDTA complex. This reduces the concentration of free lead in the blood and tissues, thereby mitigating lead toxicity.

Pharmacodynamics: The primary pharmacodynamic effect is the reduction of lead burden in the body. It also chelates other metals such as zinc, cadmium, and manganese, but with lower affinity. The drug does not cross the blood-brain barrier significantly, so it is less effective in removing lead from the central nervous system. It may increase the excretion of essential minerals like zinc and copper, which can lead to deficiencies with prolonged use.

⚑ Pharmacokinetics Summary

Absorption: Edetate calcium disodium is poorly absorbed from the gastrointestinal tract (approximately 5%). It is administered parenterally (IV, IM, SC) for systemic chelation. Oral administration is not recommended due to poor absorption and potential to increase lead absorption from the gut.
Distribution: After parenteral administration, it distributes primarily in the extracellular fluid. It does not penetrate cells or the blood-brain barrier to a significant extent. It is distributed to the kidneys, liver, and spleen.
Metabolism: The drug is not significantly metabolized; it remains as the intact chelate.
Excretion: Excretion is primarily renal, via glomerular filtration and tubular secretion. The chelated metal complexes are also excreted in the urine. Fecal excretion is minimal.
Half-Life: The elimination half-life is approximately 20-60 minutes in dogs and cats, but the chelate may be retained longer in tissues.
Bioavailability: Oral bioavailability is low (about 5%); parenteral administration provides complete bioavailability.
Protein Binding: Minimal protein binding.

Available Formulations & Strengths

Injectable Solution 200 mg/mL (as calcium disodium edetate) (IV, IM, SC)

Contraindications & Clinical Warnings

Contraindications:
  • Known hypersensitivity to edetate calcium disodium
  • Severe renal disease or anuria
  • Hepatic failure (relative contraindication)
  • Do not use orally for systemic chelation
Warnings & Clinical Precautions:
  • Use with extreme caution in patients with renal impairment; monitor renal function before and during therapy.
  • Ensure adequate hydration to promote diuresis and prevent renal toxicity.
  • May cause nephrotoxicity, especially at high doses or prolonged use.
  • Do not administer as a rapid IV bolus; infuse slowly to avoid hypotension.
  • May chelate essential minerals (zinc, copper, manganese) leading to deficiencies with prolonged therapy.
  • Use in pregnant animals only if clearly needed; safety not established.
  • In cases of lead poisoning, remove the source of lead to prevent re-exposure.

Adverse Effects & Reactions

Common:

  • Injection site pain
  • Nephrotoxicity (increased BUN/creatinine)
  • Hypocalcemia
  • Vomiting
  • Diarrhea

Serious / Severe:

  • Acute renal failure
  • Cardiovascular collapse (with rapid IV administration)
  • Severe hypocalcemia leading to tetany or seizures
  • Bone marrow suppression

Rare:

  • Anaphylactoid reactions
  • Hepatotoxicity
  • Zinc deficiency
  • Copper deficiency

Key Drug Interactions

Interacting Drug / Class Clinical Effect & Mechanism Severity
Insulin May reduce the hypoglycemic effect of insulin due to chelation of zinc (which is required for insulin crystallization). Moderate
Digoxin May increase the risk of hypokalemia and digoxin toxicity. Moderate
Corticosteroids May increase the risk of nephrotoxicity. Moderate
Other nephrotoxic drugs (e.g., aminoglycosides) Additive nephrotoxicity. High
Zinc supplements May reduce the efficacy of chelation therapy for lead poisoning. Mild

Overdose & Toxicity Management

Signs of Toxicity:

  • Acute renal failure
  • Hypocalcemia (tetany, seizures)
  • Hypotension
  • Cardiovascular collapse
  • Metabolic acidosis

Emergency Treatment Protocol: Discontinue the drug immediately. Provide supportive care including IV fluids to maintain renal perfusion and promote diuresis. Monitor serum electrolytes, especially calcium, and correct hypocalcemia with calcium gluconate if symptomatic. In severe cases, hemodialysis may be considered to remove the drug-metal complex. Symptomatic and supportive treatment is essential.

Food Animal Withdrawal Times

πŸ₯© Meat: 48 daysπŸ₯› Milk: 72 days

Withdrawal times are not officially established for edetate calcium disodium in food animals. The values provided are based on general recommendations for injectable drugs and should be used with caution. Consult regulatory authorities for specific guidance.

Storage, Handling & Regulatory Information

Storage Temperature: Store at controlled room temperature (15-30Β°C).

Handling & Special Conditions: Protect from freezing. Use only if solution is clear and colorless.

Dispensing Status: Prescription Required (Rx Only)

Approval Status: Approved for human use; not FDA-approved for veterinary use, but may be used in animals under the Animal Medicinal Drug Use Clarification Act (AMDUCA) for non-food animals.

Extra-Label (Off-Label) Use: In the US, edetate calcium disodium is not approved for veterinary use in food animals. Extra-label use in food animals is prohibited under AMDUCA due to lack of established withdrawal times and potential for violative residues. In companion animals, it is used off-label but is generally accepted.

Clinical Pearls & Practice Notes

πŸ’‘ Clinical Insights: Edetate calcium disodium is the drug of choice for lead poisoning in veterinary medicine. It is most effective when used early in the course of toxicity. Treatment should be accompanied by removal of the lead source and supportive care. Because it can cause nephrotoxicity, renal function should be assessed before and during therapy. Adequate hydration is crucial. The drug is not effective for lead in the CNS; other agents like dimercaprol or succimer may be considered for CNS involvement. In cases of zinc toxicosis, it can be used as an adjunct to gastric decontamination and supportive care. Always monitor serum calcium levels, as hypocalcemia can occur. Use with caution in young animals, as they are more susceptible to essential mineral depletion.

References & Literature

  • πŸ“š Plumb's Veterinary Drug Handbook
  • πŸ“š Papich Veterinary Pharmacology and Therapeutics
  • πŸ“š Compendium of Veterinary Products (CVP)