TREATMENT OF ACUTE AND CHRONIC LEAD POISONING WITH DISODIUM CALCIUM VERSENATE

Abstract

Effects of disodium calcium versenate (disodium calcium ethylenediamine tetra-acetate) on urinary Pb levels and symptomatology of acute and chronic Pb intoxication were studied in 5 patients. By the process of chelation the Ca ion in the stable chelate ring of the drug is replaced by the soluble bi- Pb phosphate ion due to a greater stability constant of the Pb ion which produces a marked increase in urinary Pb excretion which is maximum during the first 12 hours after therapy. Urinary Pb levels were increased as much as 20-fold in some patients after one injection of the drug. Due to the stability of the chelate ring the Pb ion is excreted in the urine in a non-toxic form. Signs, symptoms, and laboratory evidence of Pb intoxication, which included gingival lead line, abdominal pain, tremor, insomnia, mild hypertension, basophilic stippling of the red cells, elevated indirect Van den Bergh and decreased fragility to osmotic saline concentrations, all returned to normal levels within a 10 day period of therapy. No toxic effects of calcium disodium versenate were noted. It is concluded that calcium disodium versenate offers a safe and effective means of therapy in acute and chronic Pb intoxication.