Use of oral dimercaptosuccinic acid (succimer) in adult patients with inorganic lead poisoning.
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 > or = 50 microg/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.


CONCLUSIONS
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.
Bradberry
S
S
West Midland Portion Unit, City Hospital, University of Birmingham, Birmingham, B18 7QH, UK.
Sheehan
T
T
Vale
A
A
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000368:Aged; D000931:Antidotes / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D002614:Chelating Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D015913:Chelation Therapy / Q000379:methods; D004341:Drug Evaluation / Q000379:methods; D005260:Female; D006801:Humans; D007854:Lead / Q000097:blood / Q000652:urine; D007855:Lead Poisoning / Q000097:blood / Q000188:drug therapy* / Q000652:urine; D008297:Male; D008875:Middle Aged; D004113:Succimer / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D055815:Young Adult
D000931:Antidotes; D002614:Chelating Agents; D007854:Lead; D004113:Succimer