A comparative study of edetate calcium disodium and dimercaptosuccinic acid in the treatment of lead poisoning in adults

Background: We evaluated the efficacy of two antidotes, edetate calcium disodium (CaNa₂EDTA) and dimercaptosuccinic acid (DMSA), for the treatment of lead poisoning in adults.

Methods: Thirty-seven patients with blood lead concentrations >40 μg/dL and positive CaNa₂EDTA lead mobilization were randomized to receive 1050 mg/m²/day of oral DMSA (n = 21) or 500 mg/m²/day of intravenous CaNa₂EDTA (n = 16) over two five-day courses separated by a 10-day rest period. Efficacy of treatment was evaluated by blood lead assays on the first day of the two courses and 14 days after the end of treatment and baseline CaNa₂EDTA lead mobilization test and 14 days after the end of treatment.

Results and conclusion: Both treatments significantly reduced the prevalence of clinical symptoms, blood lead levels and CaNa₂EDTA lead mobilization and were well tolerated. DMSA had a greater impact on reducing blood lead concentrations (p = .005) and CaNa₂EDTA on lead mobilization (p = .04). Comparison of equimolar doses showed that CaNa₂EDTA was more effective than DMSA (p < .001).