QJM Advance Access originally published online on August 20, 2009
QJM 2009 102(10):721-732; doi:10.1093/qjmed/hcp114
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Use of oral dimercaptosuccinic acid (succimer) in adult patients with inorganic lead poisoning
From the 1West Midlands Poisons Unit, 2National Poisons Information Service (Birmingham Unit), 3School of Biosciences, University of Birmingham, 4Regional Laboratory for Toxicology, City Hospital and 5College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
Address correspondence to Professor Allister Vale, West Midland Portion Unit, City Hospital, Birmingham, B18 7QH . email: allistervale{at}npis.org
Received 20 April 2009 and in revised form 22 July 2009
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Abstract |
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Background: Chelation therapy has been used as a means of reducing the body burden of lead for five decades. Intravenous sodium calcium edetate has been the preferred agent, but there is increasing evidence that dimercaptosuccinic acid (DMSA) is also a potent chelator of lead.
Methods: Oral DMSA 30 mg/kg/day was administered to adults with blood lead concentrations 
50 µg/dl. The impact of DMSA on urine lead excretion, on blood lead concentrations and on symptoms was observed. The incidence and severity of adverse effects was also recorded.
Results: Thirty-five courses were given to 17 patients. DMSA significantly (P < 0.0001) increased urine lead excretion and significantly (P < 0.0001) reduced blood lead concentrations. Mean daily urine lead excretion exceeded the pre-treatment value by a median of 12-fold with wide variation in response (IQR 8.9–14.8, 95% CI 10.1–14.6). Pre-treatment blood lead concentrations correlated well with 5-day urine lead excretion. Headache, lethargy and constipation improved or resolved in over half the patients within the first 2 days of chelation. DMSA was generally well tolerated, but one course was discontinued due to a severe mucocutaneous reaction. There was a transient increase in alanine aminotransferase (ALT) activity during 14% of chelations. DMSA caused a significant increase in urine copper (P < 0.0001) and zinc (P < 0.05) excretion.
Conclusion: Oral DMSA 30 mg/kg/day is an effective antidote for lead poisoning, though there is a wide inter- and intra-individual variation in response.