Edetate Calcium Disodium (Calcium EDTA)

 Action Calcium is displaced by heavy metals, such as lead, to form stable EDTA complexes that are excreted in urine.

 Indications Treatment of acute and chronic lead poisoning and lead encephalopathy.

 Contraindications Anuria; active renal disease; hepatitis.

 Route/Dosage

ASYMPTOMATIC ADULTS: IV 5 ml ampule diluted with 250–500 ml normal saline or D5W. Administer dilution over at least 1 hr bid for up to 5 days. Interrupt therapy for 2 days; follow with 5 additional days if needed (maximum 50 mg/kg/day). SYMPTOMATIC ADULTS: IV 5 ml ampule diluted with 250–500 ml normal saline or D5W. Administer dilution over 2 hr. Give second daily infusion at least 6 hr after first. CHILDREN AND PATIENTS WITH OVERT OR INCIPIENT LEAD ENCEPHALOPATHY: IM 35 mg/kg bid q 8–12 hr for 3–5 days; give second course no sooner than 4 days later. Procaine or lidocaine may be added (for concentration of up to 0.5%) to minimize pain on injection.

 Interactions None well documented.

 Lab Test Interferences None well documented.

 Adverse Reactions

GU: Renal tubular necrosis.

 Precautions

Pregnancy: Safety not established. Lactation: Undetermined. Hydration: Patients may be dehydrated from vomiting. Because drug is excreted in urine, establish urine flow by IV infusion before administering first dose; then restrict IV fluid to basal water and electrolyte requirements. Lead encephalopathy: Rapid infusion may be lethal in patients with cerebral edema, because of sudden increases in intracranial pressure. IM route is preferred. Renal damage: Discontinue if urinalysis reveals large renal epithelial cells, increasing numbers of red blood cells in urinary sediment or greater proteinuria.

 Administration/Storage

• Dilute 5 ml ampule in 250–500 ml of normal saline or D5W for IV administration.
• Use infusion pump to control rate of infusion. Infuse over at least 1 hr for asymptomatic adults. Infuse over at least 2 hr for symptomatic adults.
• Administer second daily infusion no sooner than 6 hr after first dose.
• Administer IM if patient is child or has lead encephalopathy. Inject deep into well-developed muscle, and rotate injection sites. Use procaine or lidocaine to minimize pain at injection site.
• Administer dimercaprol in separate injection site if used concurrently with edetate calcium disodium.
• Administer in courses of 3–5 days, with second course given no sooner than 2 days later if given IV or 4 days later if given IM.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies.
• Assess renal function prior to and during administration, including frequent urinalysis, BUN and creatinine.
• Document serum lead level prior to and during administration.
• Assess hydration status prior to administering drug.
• Assess for signs of increased intracranial pressure prior to and during IV administration.
• Obtain baseline and periodic ECG.
• Hydrate patient with IV infusion prior to administration because patient may be dehydrated from vomiting, and then reduce rate to basal fluid and electrolyte requirements.
• Maintain strict I&O measurement and daily weights. Do not administer unless patient has adequate urine output. Discontinue drug and notify physician if anuria develops.
• Monitor vital signs and assess for paresthesia, hypotension, arrhythmias, febrile reactions and histamine-like reaction including flushing, headache, sweating, sneezing, congestion and tachycardia.
• Wait 1 hr after administering dose before drawing serum lead sample.
• Notify physician and discontinue drug if urinalysis reveals renal damage, including large epithelial cells, increased protein, RBCs or BUN.
• Rehydrate in event of anuria and continue drug once urine flow resumes.
• Discontinue IV administration and notify physician if signs of increased intracranial pressure develop.
• Obtain ECG if patient complains of palpitations or heart rate irregularities.

 Patient/Family Education

• Explain method of administration and potential side effects.
• Instruct patient to notify physician immediately if side effects occur.
• Explain rationale for strict I&O measurement and how to assist.
• Refer to public health agency regarding potential sources of lead poisoning and assistance for family in proper removal.
• Provide appropriate referrals for child who has learning deficits resulting from lead poisoning.
• Teach signs of lead poisoning, including metallic taste in mouth, abdominal cramping, GI upset, decreased urine output, alteration in mentation, blue-black line along gum, paresthesia, seizures and coma. Instruct to notify physician if any of these signs appear.
• Counsel family in low-fat diet with adequate calcium, magnesium, zinc, iron and copper to prevent binding and storage of lead in body.
• Review follow-up schedule of appointments to monitor serum lead levels.