Chelating agents for lead poisoning

Examples

Chelating agents

Generic Name	Brand Name
calcium disodium edetate or calcium EDTA (calcium disodium versenate)
dimercaprol	BAL in oil
penicillamine	Cuprimine

Dimercaprol is generally known as British anti-lewisite, or BAL.

How It Works

These medicines:

• Bind lead in tissues and increase elimination of lead in the urine.
• Reduce blood lead levels.
• Prevent further harm from lead poisoning.

Penicillamine is an antibiotic that also has a chelating effect.

Why It Is Used

Chelating agents are used if:

• Blood lead levels are 2.16 mcmol/L (45 mcg/dL) or higher (in some cases, 1.2 mcmol/L [25 mcg/dL] or higher).
• Symptoms of lead poisoning are present.
• Lead encephalopathy is present.

A course of BAL followed by calcium EDTA, given while you are hospitalized, is recommended for blood lead levels of 3.36 mcmol/L (70 mcg/dL) or higher, or when there are symptoms of lead poisoning or lead encephalopathy.

Penicillamine is used if you have unacceptable reactions to succimer and calcium EDTA. Like succimer, penicillamine is given in pills and can be taken at home.

How Well It Works

All chelating agents:

• Reduce blood lead levels.
• Reverse effects of lead poisoning on the blood.
• May cause the elimination of essential minerals, particularly calcium, magnesium, and zinc.

Side Effects

BAL

• Nausea
• Vomiting
• Fever
• Increases in blood pressure

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

• Lead sources in your home or workplace must be removed or reduced—or you need to be moved to a lead-safe home—before chelation treatment. If this is not possible, you must be hospitalized for treatment.
• Iron deficiency must be corrected either before or after chelation therapy, not at the same time. Chelation will bind to iron as well as lead and cause it to be eliminated, which can cause other health problems such as anemia.
• More than one course of treatment may be required to reduce blood lead levels.
• If a pregnant woman has a high blood lead level, the risk of exposing the fetus to chelating agents and to lead must be weighed. Referral to a centre that specializes in lead toxicity is recommended.
• Treatment with calcium EDTA or BAL or both takes 5 to 10 days. Treatment with penicillamine takes from 6 to 20 weeks.

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Author:	Douglas Dana Sydney Youngerman-Cole, RN, BSN, RNC	Last Updated: September 26, 2006
Medical Review:	Michael J. Sexton, MD - Pediatrics Tom Bailey, MD - Family Medicine R. Steven Tharratt, MD, MPVM, FACP, FCCP - Pulmonology, Critical Care, Medical Toxicology
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