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Unanswered questions in metal chelation.
J Toxicol Clin Toxicol 1992 Oct; 30(4):529-547
Chelation has been shown to increase the urinary excretion of metals, particularly demonstrated with lead (7439921) intoxicated patients. However, the author noted that while increased excretion has been well documented, whether or not the clinical outcome of the patient is improved has not been delineated. Animal studies reveal a very important time dependence to the efficacy of British-Anti- Lewisite (BAL) in averting the lethality of arsenic (7440382). The first clinical use of BAL in humans occurred in individuals suffering from a side effect known as arsenical dermatitis. Patients had a short length of hospital stay when treated with BAL; however, there is no evidence that established neuropathy is improved by the use of BAL. Studies also indicated that chelation therapy increased the urinary excretion of lead (7439921). However, in some studies BAL actually increased the toxicity of lead as well. Use of BAL plus EDTA saw a fall in mortality from lead encephalopathy to less than 5%, but at the same time there were major advances in supportive medical care and the decline in mortality cannot be attributed necessarily to the use of chelation therapy alone. As regards the effect of lead chelation on neurological endpoints in adults, there have been no randomized, placebo controlled, trials. A significant finding is that chelatable lead is not necessarily an indication of a subject's long term lead exposure. The authors ends with a concern about choosing the correct candidates for chelation.
NIOSH-Publication; NIOSH-Grant; Cardiovascular-system-disorders; Metal-poisoning; Heavy-metal-poisoning; Lead-poisoning; Arsenic-poisoning; Metal-dusts; Medical-treatment; Chelating-agents; Toxicology
Medicine University of California, SF Sfgh Bldg 30 5Th Floor San Francisco, CA 94110
7439-92-1; 7440-38-2; 7439-92-1
Issue of Publication
Journal of Toxicology: Clinical Toxicology
University of California San Francisco, San Francisco, California
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division