Chelation therapy is a widely used medicine for the treatment of heavy metal poisoning. The treatment can be administered orally or through injection into a vein or muscle. The route of administration as well as the choice of chelator agent depends on the type of poisoning.
Some of the available chelators include:
- British anti-Lewisite (BAL)
- Dimercaptosuccinic acid (DMSA)
- Dimercapto-propane-sulfonate (DMPS)
- Alpha lipoic acid (ALA)
- Ethylenediamine tetraacetic acid (EDTA)
- Diethylene triamine pentaacetic acid (DTPA)
- Deferoxamine, defriprone and deferasirox
- Ethylene glycol tetraacetic acid
- Aminophenoxyethane-tetraacetic acid (BAPTA)
- Thiamine tetrahydrofurfuryl disulfide TTFD
Uses of the chelators
British anti-Lewisite (BAL)
This substance was as an antidote for poisoning with lewisite, a chemical warfare agent containing arsenic that was used in the Second World War. Today it is used as a chelating agent in cases of poisoning with arsenic, lead, mercury and other toxic metals.
Dimercaptosuccinic acid (DMSA)
DMSA is a modified version of BAL that has less side effects. DMSA quickly replaced BAL and became the standard treatment of lead, arsenic and mercury poisoning in the U.S.
DMPS is commonly used in mercury and arsenic poisoning.
Alpha lipoic acid (ALA)
ALA is a nutritional supplement that is transformed inside the body into dithiol dihydrolipoic acid which can chelate both mercury and arsenic.
Ethylenediamine tetraacetic acid (EDTA)
This is a lead and mercury chelator. Calcium ethylenediamine tetraacetic acid (CaNaEDTA) is given as an injection to treat severe lead poisoning.
This is commonly used as a copper chelating agent in the treatment of Wilson's disease, a disorder that causes copper to build up in the body and particularly in the liver and brain. D-penicillamine is also a useful adjunctive treatment in gold, arsenic and lead poisoning.
Deferoxamine and deferasirox
These are chelating agents used to treat cases of iron overload. Iron intoxication may be caused by poisoning or by conditions such as thalassemia which requires frequent blood transfusion. With repeated transfusions, iron present in donated blood accumulates in the body.
Reviewed by Sally Robertson, BSc