Chelating agent treatment of poisoning

The most obvious treatment of poisoning from excessive metal exposure is to remove the metal from the body, thus the development of chelating agents. While treatment may be necessary, it is far more desirable to prevent exposure. In fact the best treatment for low-level exposure is often to identify the source of exposure and eliminate contact with the metal. An excellent example of this principle is lead, where the most important action is to reduce or eliminate exposure. 

Inns, R.H., Rice, P. (1993). Efficacy of dimercapto chelating agents for the treatment of poisoning hy percutaneously applied dichloro(2-chlorovinyl)arsine in rabbits. Hum. Exp. Toxicol. 12 241-6. 

The treatment of poisoning with metals includes the use of drug chelating agents. The latter form stable and non-toxic complexes with metals and are quickly eliminated from the body. 

EDTA, its sodium salt (edetate disodium, Na2EDTA), and a number of closely related compounds chelate many divalent and trivalent metals. The cation used to make a water-soluble salt of EDTA has an important role in the toxicity of the chelator. Na2EDTA causes hypocalcemic tetany. However, edetate calcium disodium (CaNa2EDTA) can be used for treatment of poisoning by metals that have higher affinity for the chelating agent than does Ca. ... 

I. Pharmacology. BAL (British anti-Lewisite, dimercaprol, 2,3-dimercaptopro-panol) is a dithiol chelating agent used in the treatment of poisoning by the heavy metals arsenic, mercury, lead, and gold. Because the vicinal thiol groups are unstable in aqueous solution, the drug is supplied as a 10% solution (100... 

Full Fanconi syndrome has been reported to be present in some children with lead encephalopathy (Chisolm 1968 Chisolm et al. 1955). According to the National Academy of Sciences (NAS 1972), the Fanconi syndrome is estimated to occur in approximately one out of three children with encephalopathy and PbB levels of approximately 150 pg/dL. Aminoaciduria occurs at PbB levels >80 pg/dL in children with acute symptomatic lead poisoning (Chisolm 1962). The aminoaciduria and symptoms of lead toxicity disappeared after treatment with chelating agents (Chisolm 1962). 

BAL is the standard treatment for poisoning by arsenic compounds and will alleviate some effects from exposure to arsenic vesicants. It may also decrease the severity of skin and eye lesions if applied topically within minutes after decontamination is complete (i.e., within 2-5 minutes postexposure). Additional chelating agents for the treatment of systemic arsenic toxicity include meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercapto-l-propanesulfonic acid (DMPS). 

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