PHARMACOKINETICS OF MESO-2,3-DIMERCAPTOSUCCINIC ACID IN PATIENTS WITH LEAD-POISONING AND IN HEALTHY-ADULTS

We compared the pharmacokinetics of meso-2,3-dimercaptosuccinic acid (DMSA) in three children with lead poisoning, three adults with lead poisoning, and five healthy adult volunteers. All subjects received DMSA orally. Maximum blood concentration and time to maximum blood concentration of total DMSA concentration were not statistically different among the groups. Unaltered DMSA was detected in the blood of all poisoned patients but in only one of five healthy volunteers. Elimination half-life of total DMSA (parent drug plus oxidized metabolites) was longer in children with lead poisoning (3.0 +/- 0.2 hours) than in adults with lead poisoning (1.9 +/- 0.4 hours) and healthy adults (2.0 +/- 0.2 hours). Renal clearance of total DMSA was greater in healthy adults (77.0 +/- 13.2 ml/min per square meter) than in either adults (24.7 +/- 3.3 ml/min per square meter) or children with lead poisoning (16.6 ml/min per square meter); renal clearance of the metabolites of DMSA was also greater in healthy adults (64.6 +/- 10.1 ml/min per square meter) than in either adults (35.4 +/- 8.6 ml/min per square meter) or children with lead poisoning (19.5 ml/min per square meter). The DMSA appeared to enter the erythrocytes of patients with lead poisoning to a greater extent than in healthy adults. We conclude that renal clearance of DMSA and its metabolites may be impaired and that the distribution of DMSA in children with lead poisoning may be different from that in adults.