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 health problem in developed and developing countries. Chelation therapy particularly wi th calcium disodium ethelenediamine tetraacetic acid (CaNa(2)EDTA) is often used therapeutically to reduce the body burden of lead. This che lating drug has serious side effects and drawbacks primarily related t o redistribution of lead, nephrotoxicity, and essential metal depletio n. The present study was planned to determine the effectiveness of CaN a(2)EDTA and meso-2,3-dimercaptosuccinic acid (DMSA) used in combinati on. Both drugs, when administered individually, resulted in significan t urinary excretion of lead and lowered the tissue lead burden. Combin ed treatment with CaNa(2)EDTA and DMSA elicits an additive response in promoting urinary lead elimination, depleting body lead burden, and r estoring altered lead-sensitive biochemical variables. Further, no red istribution of lead to brain or any other soft organ following combine d DMSA-CaNa(2)EDTA treatment was observed indicating a definite advant age of combined therapy over the conventional treatment with CaNa(2)ED TA or DMSA alone. However, an elevation of serum transaminase activity , creatinine level, and depletion of blood zinc level may limit the us efulness of this combined treatment. (C) 1995 Society of Toxicology.