Chelating agents for lead poisoning

Chelating agents

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

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.

Chelating agents are used if:

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

Succimer is recommended for treating blood lead levels ranging from 45 to 70 micrograms per deciliter (mcg/dL) when there are no symptoms of lead poisoning. Succimer is given by mouth and is the treatment of choice if you can be treated at home.

A course of BAL followed by calcium EDTA, given while you are hospitalized, is recommended for blood lead levels of 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.

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.

Succimer

• Abdominal pain
• Nausea
• Vomiting
• Diarrhea
• Chills
• Fever
• Hives
• Rashes

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.)

• 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 center that specializes in lead toxicity is recommended.
• Treatment with calcium EDTA or BAL or both takes 5 to 10 days. Treatment with succimer takes 19 days. Treatment with penicillamine takes from 6 to 20 weeks.

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