<unk>  was approved for medical use in the United States in 1970. It is on the World Health Organization's List of Essential Medicines. It is used as a chelating agent: * In Wilson's disease, a rare genetic disorder of copper metabolism,<unk>  treatment relies on its binding to accumulated copper and elimination through urine. *<unk>  was the second line treatment for arsenic poisoning, after dimercaprol (BAL). It is no longer recommended. In cystinuria, a hereditary disorder in which high urine cystine levels lead to the formation of cystine stones,<unk>  binds with cysteine to yield a mixed disulfide which is more soluble than cystine.<unk>  has been used to treat scleroderma.<unk>  can be used as a disease-modifying antirheumatic drug (DMARD) to treat severe active rheumatoid arthritis in<unk> tients who have failed to respond to an adequate trial of conventional therapy, although it is rarely used today due to availability of TNF inhibitors and other agents, such as tocilizumab and tofacitinib.<unk>  works by reducing numbers of T-lymphocytes, inhibiting macrophage function, decreasing IL-1, decreasing rheumatoid factor, and preventing collagen from cross-linking.
Penicillamine
Zinc pyrithione
Hydroxocobalamin
Cyanocobalamin
Penicilloic acid
Zinc sulfate 
Deferoxamine
Sodium thiosulfate 