The effect of 2,3 dimercaptosuccinic acid in the treatment of lead poisoning in adults.

Four patients, aged 22-60, belonging to a single family that had been exposed to lead-contaminated food for an unknown period, and nine workers, aged 20-65, who had been exposed to air-borne lead for 6-8 years, were evaluated for lead poisoning in our centres. Blood lead levels were 3.57 +/- 0.39 micromol/L (mean +/- SD) in the family members and 3.46 +/- 0.43 micromol/L (mean +/- SD) in the group of workers. 2,3 dimercaptosuccinic acid (DMSA) therapy was instituted in the four family members while the nine workers were closely monitored after being removed from the contaminated environment without receiving any chelation therapy. DMSA therapy given for the duration of 19 days reduced the blood lead levels to 0.63 +/- 0.44 micromol/L (mean +/- SD), P<0.01, in the four family members. No significant change was observed in the untreated group. The exposure time in the untreated group was probably longer than that in the treated group. Following long-term exposure most of the lead in the body is found in the bones and therefore not easily removed by chelation therapy. No side-effects were reported in the treated group and no rebound elevation of blood lead levels was observed during the therapy period or during the 12-week follow-up period following cessation of therapy. We conclude that 19 days of chelation therapy with DMSA in adults with moderate to severe lead poisoning is effective and safe.