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 with calcium disodium ethelenediamine tetraacetic acid (CaNa(2)EDTA) is often used therapeutically to reduce the body burden of lead. This chelating drug has serious side effects and drawbacks primarily related to redistribution of lead, nephrotoxicity, and essential metal depletion. The present study was planned to determine the effectiveness of CaNa(2)EDTA and meso-2,3-dimercaptosuccinic acid (DMSA) used in combination. Both drugs, when administered individually, resulted in significant urinary excretion of lead and lowered the tissue lead burden. Combined treatment with CaNa(2)EDTA and DMSA elicits an additive response in promoting urinary lead elimination, depleting body lead burden, and restoring altered lead-sensitive biochemical variables. Further, no redistribution of lead to brain or any other soft organ following combined DMSA-CaNa(2)EDTA treatment was observed indicating a definite advantage of combined therapy over the conventional treatment with CaNa(2)EDTA or DMSA alone. However, an elevation of serum transaminase activity, creatinine level, and depletion of blood zinc level may limit the usefulness of this combined treatment. (C) 1995 Society of Toxicology.