It is used as a chelating agent:
* In Wilson's disease, a rare genetic disorder of copper metabolism, penicillamine treatment relies on its binding to accumulated copper and elimination through urine.
* Penicillamine 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, penicillamine binds with cysteine to yield a mixed disulfide which is more soluble than cystine.
Penicillamine has been used to treat scleroderma.
Penicillamine can be used as a disease-modifying antirheumatic drug (DMARD) to treat severe active rheumatoid arthritis in patients 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. Penicillamine works by reducing numbers of T-lymphocytes, inhibiting macrophage function, decreasing IL-1, decreasing rheumatoid factor, and preventing collagen from cross-linking.