Safety and efficacy of succimer in toddlers with blood lead levels of 20-44 mu g/dL

Although lead encephalopathy has virtually disappeared from the United Stat es, thousands of children still have sufficient lead exposure to produce co gnitive impairment. It is not known whether treating children with blood le ad levels < 45 <mu>g/dL (2.2 muM) is beneficial and can be done with accept able safety. We conducted a 780-child, placebo-controlled, randomized trial of up to three courses of succimer in children with blood lead levels of 2 0-44 mug/dL (1.0-2.1 muM). Children were aged 12-33 mo, 77% were African-Am erican, 7% were Hispanic, and they Lived in deteriorating inner city housin g. Placebo-treated children had a gradual decrease in blood lead level. Suc cimer-treated children had an abrupt drop in blood lead level, followed by rebound. The mean blood lead level of the succimer-treated children during the 6 mo after initiation of treatment was 4.5 mug/dL (95% confidence inter vals, 3.7 to 5.3 mug/dL; 0.22 muM, 0.18 to 0.26 muM) lower than that of pla cebo-treated children. There were more scalp rashes in succimer-treated chi ldren (3.5% versus 1.3%) and an unanticipated excess of trauma. Succimer lo wers blood lead level with few side effects. The unanticipated excess of tr auma requires confirmation.