Pharmacology · Chelating agents
Succimer !
An oral sulfhydryl chelator (DMSA) for lead poisoning, especially in children, and for arsenic and mercury.
Updated 2026-11-01
Also called: DMSA, meso-2,3-dimercaptosuccinic acid
Mechanism of action
Succimer is a water-soluble analogue of dimercaprol with two sulfhydryl groups. It binds lead, arsenic and mercury in water-soluble chelates that are excreted in urine, lowering blood lead. It has a higher therapeutic index than dimercaprol and, because it is oral, it is the usual choice for lead poisoning in children without encephalopathy.
- Taken by mouth and absorbed
- Two -SH groups bind lead, arsenic or mercury
- Water-soluble chelates leave in urine
- Blood lead falls; exposure must also stop
Pharmacokinetics
- Absorption
- Absorbed by mouth
- Elimination
- Kidneys, as metal chelates
Indications
- Lead poisoning, particularly in children, where edetate is avoided Lead poisoning →
- Arsenic poisoning Arsenic poisoning →
- Inorganic, elemental and organic mercury poisoning Mercury poisoning →
Adverse effects
Common
- Rash
- Raised liver enzymes
- Eosinophilia
Contraindications
- Previous hypersensitivity to succimer
Key interactions
- Continued exposure to lead
- Chelation does not replace removing the source; levels rise again if exposure continues
What is monitored
- Blood lead before, during and after each course
- Liver enzymes
- Complete blood count (neutrophils)
- Kidney function
Administration and safety
- Taken by mouth; the capsule can be opened and mixed with soft food for children who cannot swallow it
- The patient is well hydrated before treatment
Nursing care
- Teach the family how to give the capsule contents with food
- Report rash, fever or sore throat
- Help identify the lead source at home or work
- Schedule follow-up blood lead tests
Pregnancy and breastfeeding
Data are limited (category C in the Colombian guide); breastfeeding is stopped until blood lead has fallen.
Test yourself
Think of the answer, then tap the question to see it.
What advantage does succimer have over dimercaprol and edetate?
It is taken by mouth and has a higher therapeutic index, so it suits children with lead poisoning without encephalopathy.
Which laboratory tests are followed during succimer treatment?
Blood lead, liver enzymes, blood count and kidney function.
What must accompany chelation in lead poisoning?
Finding and removing the source of exposure.
Related drugs
Related conditions
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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Guía para el Manejo de Emergencias Toxicológicas (Ministerio de Salud y Protección Social; Organización Panamericana de la Salud, 2017); Farmacología básica y clínica (Katzung), 16.ª ed., cap. 57 (McGraw Hill, 2025); eEML - Electronic Essential Medicines List (World Health Organization, 2025); DailyMed - EDETATE CALCIUM DISODIUM injection (DailyMed (U.S. National Library of Medicine), 2026).
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