cysteamine

Cysteamine is a small molecule drug used primarily to treat nephropathic cystinosis, a rare genetic lysosomal storage disorder caused by mutations in the CTNS gene. This condition leads to the accumulation of cystine crystals in various organs, especially the kidneys and eyes. Cysteamine acts as a cystine-depleting agent by entering lysosomes and participating in thiol-disulfide interchange reactions with stored cystine, converting it into compounds that can exit the lysosome and be excreted from cells[2][3][7]. This reduces tissue damage from crystal buildup. Oral formulations (Cystagon, Procysbi) are approved for systemic treatment; an ophthalmic solution (Cystaran) is available for corneal involvement[2][3][7]. Topical forms are also used off-label for skin depigmentation disorders such as melasma due to their ability to inhibit tyrosinase and peroxidase activity[8]. Additional mechanisms include antioxidant effects via increased glutathione production and inhibition of pro-apoptotic caspase 3 activity[6].

Brand names

CystagonProcysbiCystaran

Other names

cysteamine bitartrate