Medical Toxicologists Determine Chelation Therapy Rarely Necessary

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Experts from the American College of Medical Toxicology, the Centers for Disease Control, the Agency for Toxic Substances and Disease Registry, and others met at the CDC to review the current use and misuse of chelation therapy in the United States for the treatment of metal poisoning. It was concluded that incorrect diagnosis of metal poisoning is common, and inappropriate use of chelation therapy is widespread.

American College of Medical Toxicology elevated concentration of a metal in the urine following administration of a chelating agent is often incorrectly presented to the patient as evidence of metal poisoning."

Medical toxicologists and scientific experts speaking at a recent conference at the Centers for Disease Control in Atlanta criticized the widespread misdiagnosis of poisoning from lead, arsenic, mercury and other metals, and called for strong efforts to decrease the inappropriate use of metal chelation therapy.

Chelating agents are medications that may be given to patients to increase elimination of metals from the body. Traditionally chelating agents have been used to treat acute poisoning following a large exposure to a metal such as arsenic, mercury, or lead. In recent years, the administration of chelating agents by some health providers has increased. Although chelating agents such as calcium EDTA, DMSA, and DMPS are medications intended to be prescribed by licensed physicians, they are often sold to patients by health care practitioners or obtained without a prescription over the internet, possibly in violation of federal regulations.

It has been estimated that nearly 200,000 people may be treated with chelating agents each year in the United States. These patients are frequently diagnosed with chronic metal poisoning based on a poorly documented environmental exposure, vague clinical findings, and inappropriate diagnostic testing. A provoked urine metals test, also called a urine mobilization or challenge test, is a controversial practice in which a chelating drug is given to a patient prior to collection of their urine for metal analysis. Chelating agents produce an elevated concentration of metal in the urine even in healthy patients, and such an increase should not be used to diagnose metal poisoning. The presence of an elevated concentration of a metal in the urine following administration of a chelating agent is often incorrectly presented to the patient as evidence of metal poisoning, leading to expensive chelation treatments. It was widely agreed that this practice should be abandoned, supporting the position adopted by the American College of Medical Toxicology on this issue in 2009.

There is no credible scientific evidence to support the use of chelation in the majority of individuals with chronic metal exposure, the patient population that appears to most frequently receive these treatments. Although chronic exposure to certain metals such as lead has been associated with adverse health effects, studies have not found that chelation therapy improves patient outcomes. Instead, prompt removal from the source of elevated metal exposure is recommended, and in most cases that alone will represent the cornerstone of effective medical intervention. Inappropriate use of chelating drugs can cause serious, even life-threatening, adverse reactions, particularly in patients who do not have metal poisoning.

Findings from the ACMT event 'Use and Misuse of Metal Chelation Agents' will be published as proceedings in the Journal of Medical Toxicology. The ACMT strongly recommends that all people with concerns about possible metal poisoning contact a medical toxicologist. A national directory of board-certified medical toxicologists can be found at

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Anne-Michelle Ruha, M.D.
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