Lead Poisoning
Medications
Chelating agents are used for severe lead poisoning. Chelating agents are medicines that bind with lead in blood and both soft and bony tissues and eliminate it quickly from the body, usually through the urine.
The use of chelating agents for lead poisoning is still being studied, and there is no single treatment or drug of choice. In general, drug treatment is recommended when blood lead levels are above 2.16 micromoles per litre (mcmol/L) or 45 micrograms per decilitre (mcg/dL) or when there are symptoms of lead poisoning, especially lead encephalopathy.
There is disagreement over whether chelation therapy is needed for children with blood lead levels between 1.2 mcmol/L and 2.1 mcmol/L (25 mcg/dL and 44 mcg/dL)—one study showed no benefit to the child.15 Reducing or removing environmental lead sources, correcting iron deficiency, and improving nutrition may be enough to lower lead levels in the blood. The decision to use chelating agents depends on how long the child has been exposed to lead, how high the blood lead level is, what the symptoms are, and whether the blood lead level remains high even after the source of lead is removed or reduced and nutrition is improved.
In theory, chelating agents prevent further damage by reducing blood lead levels rapidly. Damage to the blood may repair itself if blood lead levels are lowered. Kidney damage may also heal, unless it has been too extensive. Chelation therapy may not reverse central nervous system (brain and spinal cord) damage that has already occurred.
Medication Choices
Chelating agents are chemicals that bind with lead for the treatment of lead poisoning.
What To Think About
Chelating agents increase absorption of lead and other metals. A person exposed to lead while taking a chelating agent may absorb more of the lead, thus defeating the purpose of the therapy and possibly doing even more harm. Therefore, it is essential that lead sources be removed from your environment before treatment. (This may require that treatment be administered in a hospital.) Do not return home or to the workplace until lead sources have been removed.
Results need to be reported to the local health unit if 2 or more blood lead levels are above 0.48 micromoles per litre (mcmol/L) (10 micrograms per decilitre [mcg/dL]). A home inspection is needed to find the source of the lead contamination.
If blood lead levels do not come down with treatment, your home and work areas need to be rechecked for other sources of lead. Contact your local health unit to see what inspection services are available in your area.
Iron deficiency also increases lead absorption. Iron deficiency cannot be treated at the same time as chelation therapy because the chelating drug will bind to iron and remove it as well. Iron deficiency must be treated either before or after chelation therapy.
Chelation therapy does reduce blood lead levels and may slow down problems with kidney function associated with lead poisoning.16 However, it does not appear to improve cognitive damage or other neurological problems already caused by the lead poisoning.15 If chelation therapy is necessary, it is best to consult with a doctor experienced with this treatment.
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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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