Toxicokinetics of mercury elimination by succimer in twin toddlers.

We describe the toxicokinetics of mercury in two twin toddlers poisoned by an East Indian remedy for teething. Succimer (dimercaprosuccinic acid, DMSA) decreased the plasma elimination half-life of mercury by 3-fold in the patient with high exposure; a more modest effect was observed in the other twin. Succimer is a chelation agent used in the treatment of heavy metal intoxication. A water-soluble agent, it increases the urinary excretion of lead and mercury. The drug is rapidly but variably absorbed through the gastrointestinal tract, with peak levels occurring at 1-2 hours. After its absorption, peak mercury excretion through the urine occurs within 2-4 hours. In the poisoned twin sisters, succimer administration led to a mercury plasma elimination half-life of 6 weeks. Although succimer has been used in mercury poisoning in adults and children, the toxicokinetics of mercury have not previously been characterized in either age group. We believe this is the first such description. More studies on the toxicokinetics and dynamics of mercury chelation with succimer in young children are needed to ensure the optimal use of the drug in this population.