Cysteamine

What it is and how it works

Mechanism of Action Cysteamine acts as a cystine-depleting agent by converting cystine to cysteine and cysteine-cysteamine mixed disulfides and reduces corneal cystine crystal accumulation.

Indications

is a cystine-depleting agent indicated for the treatment of corneal cystine crystal deposits in adults and children with cystinosis. CYSTADROPS is a cystine-depleting agent indicated for the treatment of corneal cystine crystal deposits in adults and children with cystinosis.

Dosage and administration (summary)

Instill one drop of CYSTADROPS in each eye, 4 times a day during waking hours. Dosage Information Instill one drop of CYSTADROPS in each eye, 4 times a day during waking hours. Do not touch dropper tip to the eyelids, surrounding areas, or any surface, as this may contaminate the solution. In case of concomitant therapy with other topical ocular products, an interval of 10 minutes should be allowed between successive applications. Eye ointments should be administered last. If the patient misses an instillation, the patient should be told to administer a dose as soon as feasible and then continue the treatment with the next scheduled instillation. Discard bottle 7 days after first opening.

Contraindications

None. None.

Warnings and precautions

To minimize the risk of contamination, do not touch the dropper tip to any surface. Keep bottle tightly closed when not in use. Contamination of Tip and Solution To minimize contaminating the dropper tip and solution, care should be taken not to touch the eyelids or surrounding areas with the dropper tip of the bottle. Keep bottle tightly closed when not in use. Benign Intracranial Hypertension There have been reports of benign intracranial hypertension (or pseudotumor cerebri) associated with oral cysteamine treatment that has resolved with the addition of diuretic therapy.

Pregnancy

Pregnancy Risk Summary There are no adequate and well-controlled studies of ophthalmic cysteamine in pregnant women to inform any drug associated risks. Oral administration of cysteamine to pregnant rats throughout the period of organogenesis was teratogenic at doses 240 to 960 times the recommended human ophthalmic dose (based on body surface area…

Storage and supply

(cysteamine ophthalmic solution) 0.37% is supplied as a 5 mL sterile viscous solution in a 10 mL amber glass bottle closed by a bromobutyl stopper and sealed with an aluminum tear-off cap. A PVC dropper applicator with HDPE closure is packed separately and included in each carton box.

Source: Cysteamine Hydrochloride (Cystadrops) — US FDA prescribing information, 2025-06-06, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.