edetate disodium (EDTA)
Disotate, Endrate

Available forms
Available by prescription only
Injection: 150 mg/ml

Indications and dosages
 Hypercalcemia. Adults: 50 mg/kg daily by slow I.V. infusion to maximum of 3 g in 24 hours. Dilute in 500 ml of D₅W or normal saline solution. Give over 3 hours or longer.
Children: 40 mg/kg by slow I.V. infusion, diluted to a maximum of 30 mg/ml in D₅W or normal saline solution and given over 3 hours or longer. Maximum dosage is 70 mg/kg daily.
 Cardiac glycoside-induced ventricular arrhythmias. Adults and children: I.V. infusion of 15 mg/kg/hour. Maximum dosage is 60 mg/kg daily. Dilute in D₅W.

Pharmacodynamics
Chelating action: Binds many divalent and trivalent ions but has the strongest affinity for calcium, with which it forms a stable complex readily excreted by the kidneys. Also chelates magnesium, zinc, and other trace metals, increasing their excretion in urine; doesn’t decrease CSF calcium levels.

Pharmacokinetics
Absorption: Administered I.V.
Distribution: Doesn’t enter CSF in significant amounts but is distributed widely throughout rest of body.
Metabolism: None.
Excretion: After I.V. administration, is excreted rapidly in urine; 95% of dose excreted within 24 hours.

Contraindications and precautions
Contraindicated in patients hypersensitive to drug and in those with anuria, known or suspected hypocalcemia, significant renal disease, active or healed tubercular lesions, or history of seizures or intracranial lesions.
 Use cautiously in patients with limited cardiac reserve, heart failure, or hypokalemia.

Interactions
Drug-drug. Cardiac glycosides: Indirectly interferes with cardiac effects of cardiac glycosides by decreasing intracellular calcium via chelation and urinary excretion of extracellular calcium. Monitor patient.
Insulin: Requirements may be decreased by chelation of zinc in exogenous insulin. Monitor serum glucose levels.

Adverse reactions
CNS: circumoral paresthesia, numbness, tetany, headache, seizures.
CV: hypotension, thrombophlebitis.
GI: nausea, vomiting, diarrhea.
GU: nephrotoxicity with urinary urgency, nocturia, dysuria, polyuria, proteinuria, renal insufficiency, acute renal failure, acute tubular necrosis.
Metabolic: severe hypocalcemia, decreased magnesium level, hypoglycemia.
Skin: exfoliative dermatitis, erythema.
Other: pain at infusion site, extravasation.

Effects on lab test results
• May decrease glucose, alkaline phosphatase, calcium, and magnesium levels.

Overdose and treatment
Effects of overdose include hypotension, arrhythmias, respiratory arrest, and cardiac arrest.
 Treat hypotension with fluids, if indicated. Treat arrhythmias with lidocaine and seizures and tetany with calcium replacement. Use I.V. diazepam for refractory seizures. Replace magnesium and potassium as needed.

Special considerations
• Don’t exceed recommended rate of infusion or dosage; rapid infusion or high levels of edetate disodium may greatly decrease serum calcium levels, causing seizures and death. Have I.V. calcium replacement readily available whenever drug is given.
• Drug also has been used topically or by iontophoresis to treat corneal calcium deposits.
• Monitor serum calcium and potassium levels before treatment. Monitor serum calcium level, ECG, and vital signs continuously throughout therapy.
• Monitor infusion site closely. Extravasation severely irritates tissue; rotate infusion sites with multiple doses or long-term therapy.
• Monitor serum glucose level if patient is diabetic.
Pediatric patients
• Give recommended dose slowly, over at least 3 hours.
Geriatric patients
• Elderly patients with renal or cardiac failure are at increased risk; lower doses are recommended.

Patient education
• Explain possible adverse reactions; stress importance of reporting signs and symptoms promptly.
• Tell diabetic patient that insulin dosage may need adjustment.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use