<unk>  has long been the mainstay of chelation therapy for lead or arsenic poisoning, and it is an essential drug. It is also used as an antidote to the chemical weapon Lewisite. Nonetheless, because it can have serious adverse effects, researchers have also pursued development of less toxic analogues, such as succimer. Wilson's disease is a genetic disorder in which copper builds up inside the liver and other tissues.<unk>  is a copper chelating agent that has been approved by the FDA to treat Wilson's disease.<unk>  also shows effectiveness against snakebite by potently antagonizing the activity of Zn2+-dependent snake venom metalloproteinases in vitro.
Dimercaprol
Fomepizole
Disufenton sodium
Dimercaptosuccinic acid
Mercapturic acid
Sodium thiosulfate 
Methylene blue
Sodium fluoroacetate