Medication Summary
In patients with lead toxicity, the use of chelating agents is recommended for blood lead levels (BLLs) of 45 μg/dL or higher. Chelation can be started with oral succimer, or, if the patient is hospitalized, calcium disodium edetate (calcium EDTA) can be used. These agents have potential toxicities, and monitoring of the complete blood cell count, electrolytes, and liver function test results is necessary.
Chelating Agents
Class Summary
Chelating agents are the criterion standard for the treatment of patients with lead poisoning according to the blood lead levels (BLLs) discussed above. These agents bind to lead and promote its excretion. Patients receiving chelation therapy must be closely monitored because of the agents' potential toxicities.
Dimercaprol (BAL in oil)
Dimercaprol was first developed as an antidote for lewisite toxicity. It is water soluble and rapidly crosses the blood-brain barrier. Dimercaprol forms a nonpolar compound with lead that is excreted in bile and urine. It is the drug of choice in patients with acute lead encephalopathy, in whom the first dose is given and then the second dose is given combined with calcium EDTA after a 4-hour interval.
Edetate calcium disodium (Calcium Disodium Versenate)
This agent decreases blood lead concentration, reverses the hematologic effects of lead, and enhances the excretion of lead in urine.
Succimer (Chemet)
Dimercaptosuccinic acid (DMSA) is a water-soluble analog of dimercaprol. It causes a rapid decline in lead level and replenishes many of the sulfhydryl-dependent enzymes. In the absence of encephalopathy, patients may be treated with DMSA.
D-penicillamine (Cuprimine, Depen)
D-penicillamine is also known as D-dimethyl cysteine. It offers an alternative for oral treatment of lead poisoning. This agent is not approved by the US Food and Drug Administration (FDA) for use in lead poisoning, but has nonetheless been in use for more than 20 years.
