[Treatment of chronic occupational lead poisoning with dimercaptosuccinic acid (DMSA)]

2,3-dimercaptosuccinic acid (DMSA) mobilizes lead from superficial depots. In comparison with other chelating agents, DMSA has a high therapeutic index and has the additional advantage that it can be administered orally. We have used DMSA for treatment of chronic occupational lead poisoning in a 54-year old male with signs of neurotoxic effects. The treatment resulted in a rapid decrease in the blood-lead concentration, followed by a slow increase after the treatment and subsequent stabilization at a blood-lead level lower than prior to treatment. During the first course of treatment, almost 100 mumols lead was excreted in the urine. As a result of successive courses of treatments, the patient's condition was improved. However, during the third course of treatment, he developed a mucocutaneous rash which faded again after withdrawal of DMSA; this reaction was subsequently provoked by sub-therapeutic doses, and continued treatment was therefore cancelled. Only minor, reversible side effects of DMSA have hitherto been reported, and DMSA must therefore be regarded a promising agent for long-term, out-patient chelation treatment of chronic lead poisoning.