Combined Therapeutic Potential of meso-2,3-Dimercaptosuccinic Acid and Calcium Disodium Edetate on the Mobilization and Distribution of Lead in Experimental Lead Intoxication in Rats

Asymptomatic lead poisoning remains a serious public healthproblem in developed and developing countries. Chelation therapyparticularly with calcium disodium ethelenediamine tetra-aceticacid (CaNa₂EDTA) is often used therapeutically to reduce thebody burden of lead. This chelating drug has serious side effectsand drawbacks primarily related to redistribution of lead, nephrotoxicity,and essential metal depletion. The present study was plannedto determine the effectiveness of CaNa₂EDTA and meso-2,3-dimercaptosuccinicacid (DMSA) used in combination. Both drugs, when administeredindividually, resulted in significant urinary excretion of leadand lowered the tissue lead burden. Combined treatment withCaNa₂EDTA and DMSA elicits an additive response in promotingurinary lead elimination, depleting body lead burden, and restoringaltered lead-sensitive biochemical variables. Further, no redistributionof lead to brain or any other soft organ following combinedDMSA-CaNa₂EDTA treatment was observed indicating a definiteadvantage of combined therapy over the conventional treatmentwith CaNa₂EDTA or DMSA alone. However, an elevation of serumtransaminase activity, creatinine level, and depletion of bloodzinc level may limit the usefulness of this combined treatment.