DMSA and DMPS-Water Soluble Antidotes for Heavy Metal Poisoning

Abstract

This article reviews the pharmacological properties and the uses of two important antidotes for heavy metal poisoning. Meso-dimercaptosuccinic acid (DMSA) and 2,3-dimercapto-l-propanesulfonic acid, Na salt (DMPS) are relatively new antidotes-new, that is, to the western world. Although DMSA was introduced originally by Friedheim et al (1) to increase uptake of antimony during schistosomiasis therapy, Liang et al (77) at Shanghai in 1957 were the first to report its effectiveness as an antidote for heavy metal poisoning. The synthesis and some of the metal binding properties of DMPS were reported in 1956 by Petrunkin from Kiev (3). Shortly thereaf­ ter, DMPS became an official drug in the Soviet Union, where it is known as Unithiol (4). Between 1956 and 1975, DMSA and DMPS were studied extensively, at both the basic science and clinical levels, in the People's Republic of China, the Soviet Union, and Japan. Some of these investigations have been cited and can be found in an earlier review (5). In the USA and western Europe, however, these two compounds received very little attention until recently. A paper by Friedheim & Corvi (6) in 1975, dealing with DMSA for the treatment of mercury poisoning, and the recent production and availability of DMPS from Heyl & Co., Berlin, stimulated investigators to rediscover and study these two metal-binding agents. DMSA and DMPS are water soluble chemical analogs of dimercaprol (British Anti-Lewisite, BAL). In contrast to BAL, they have less toxicity, greater water solubility, and lim­ ited lipid solubility, and are effective when given orally.