Cystine depleting agents are used to treat nephropathic cystinosis and ocular cystinosis. These medications work by reducing the levels of cystine in your body, which helps prevent the formation of crystals that can damage organs and tissues. Cystine depleting agents come in different forms, including oral capsules, granules, and eye drops. Examples include oral cysteamine (Cystagon), cysteamine ophthalmic solution (Cystaran, Cystadrops), and oral delayed-release cysteamine (Procysbi).