Medical treatment British Anti-Lewisite

A special derivatization reaction is required for lewisite 1, which is so reactive that it cannot be determined by GC/MS in low quantities (e.g. below 10 ng per injection). It has been known for a long time that lewisite 1 reacts with compounds having an a, P-dithiol structure, such as 2,3-dimercaptopropanol-l (British-Anti-Lewisite (BAL) also used for medical treatment). The derivatization reaction can be performed at an analytical level and several examples have been described (29). The reaction product of lewisite 1 with 3,4-dimercaptotoluene, 2-(2-chlorovinyl)-5-methyl-l,3,2-benzodithiarsole (see (1)), is a useful derivative for GC/MS analysis. Its mass spectrum is simple with molecular ion peaks at m/z 290/292 and the base peak at m/z 229 due to the loss of the 2-chlorovinyl group (30). 

In acute exposure prompt medical attention is critical. The victim should be immediately removed to fresh air and away from the source of exposure. Oxygen should be provided if there is a respiratory distress. Initial therapy should be directed at stopping the ongoing hemolysis by performing exchange transfusion. Currently there is no other treatment to decrease arsine hemolysis however, studies in vitro have shown that some dithiol chelators (meso-2,3-dimercaptosuccinic acid, DMSA 2,3-dimercapto-l-propanesulfonic acid, DMPS and 2,3-butanedithiol) are effective (see Further Reading). This should be followed by aims to restore renal function or compensate for lost renal function (hemodialysis). This process does not remove any formed arsenic from the exposed body. Administration of dimercaprol (British Anti-Lewisite, BAL) has no effect on arsine hemolysis, but it lowers blood arsenic levels resulting from arsine exposure. The use of chelators must be... 

Medical treatment with chelation uses four different agents British Anti-Lewisite (2,3-dimercaptopropanol), edetate calcium disodium, D-penicillamine, and succimer or meso-2,3-dimercaptosuccinic acid (Roper et al. 1993). British Anti-Lewisite is contraindicated in children allergic to peanuts and in glucose-6-phosphate dehydrogenase deficiency D-penicillamine is contraindicated in penicillin allergy (Roper et al. 1993). 

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