Dimercaptosuccinic acid

Dimercaptosuccinic acid (DMSA), is the organosulfur compound with the formula HO₂CCH(SH)CH(SH)CO₂H. This colorless solid contains two carboxylic acid and two thiol groups, the latter being responsible for its mildly unpleasant odour. It occurs in two diastereomers, meso and the chiral dl forms. The meso isomer is used as a chelating agent. The acid is most often used as a treatment for heavy metal toxicity, and is a water-soluble and non-toxic substance.

It is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system.

Medical uses

Dimercaptosuccinic acid (CHEMET) is indicated for the treatment of lead poisoning in children with blood level measured above 45 µg/dL. The use of DMSA is not approved for prevention of lead poisoning in anticipation of exposure in known lead contaminated environments. Its elimination half-life is 2.5-3.5 h. DMSA can cross the blood–brain barrier of mice, but not that of humans, limiting its use to extracting heavy metals from parts of the body other than the central nervous system.