The pharmacology of 2,3-dimercaptosuccinic acid and its potential use in arsenic poisoning

Arsenic (As2O3)-poisoned rats were treated with either 2,3-dimercaptosuccinic acid (DMS) or dimercaptopropanol (BAL) at doses of 30 mg/kg/day. A control group received no treatment. The total quantity of arsenic excreted was not significantly different in response to 4 days of treatment with either DMS or BAL. In addition, there was no difference between the two drug treatment groups in the residual arsenic content of brain, liver, kidney and spleen after treatment. Both drugs reduced the arsenic content of each tissue to approximately 40% of that of untreated controls. Previous studies have shown that DMS is orally effective for the treatment of lead poisoning. The LD50 of DMS was determined to be in excess of 3 g/kg in rats and mice, approximately 30 times the LD50 of BAL. No gross, histopathological or biochemical evidence of toxicity was observed in mice, rats or dogs which received DMS 5 days per week for 6 months. DMS did not affect the excretion of zinc, iron, calcium or magnesium. Urinary copper excretion was significantly elevated in response to 30 mg/kg of DMS, suggesting that the drug might also be useful for the treatment of Wilson's disease.