Succimer, a drug used for treating lead poisoning, does not effectively remove mercury from the body, according to research supported by the National Institutes of Health. Some families have turned to succimer as an alternative therapy for treating autism.
"Succimer is effective for treating children with lead poisoning, but it does not work very well for mercury," said Walter Rogan, M.D., head of the Pediatric Epidemiology Group at the National Institute of Environmental Health Sciences (NIEHS), part of NIH, and an author on the paper that appears online in the Journal of Pediatrics.
"Although it is not approved by the Food and Drug Administration to reduce mercury, succimer is reportedly being used for conditions like autism, in the belief that these conditions are caused, in part, by mercury poisoning," Rogan stated. "Our new data offers little support for this practice."
Although researchers found that succimer lowered blood concentrations of mercury after one week, continued therapy for five months only slowed the rate at which the children accumulated mercury. The safety of higher doses and longer courses of treatment has not been studied.
Most mercury exposure in the United States is from methylmercury, found in foods such as certain fish. Thimerosal, a preservative that was once more commonly used in vaccines, contains another form of mercury, called ethylmercury.
To conduct the study, the researchers used samples and data from an earlier clinical trial, led by NIEHS, called the Treatment of Lead-exposed Children (TLC) trial. In the TLC study, succimer lowered blood lead in 2-year-old children with moderate to high blood lead concentrations.
Using blood samples from 767 children who participated in the TLC trial, the researchers measured mercury concentration in the toddlers' blood samples collected before treatment began, one week after beginning treatment with succimer or placebo, and t
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NIH/National Institute of Environmental Health Sciences