Does cysteamine expire?
The printed date covers the sealed pack. Once cysteamine is opened, mixed or diluted, its label sets a second and usually much shorter limit — quoted below, per product.
Shortest limit on any cysteamine label: 7 days
“Discard 7 days after first opening.”
That applies to the product it is printed on, not to every form of cysteamine — check which one you have against the list below.
What the labels say
“Discard 7 days after first opening.”
On the label for CYSTADROPS · DailyMed
“Discard bottle 7 days after first opening.”
On the label for CYSTADROPS · DailyMed
“There may be medication left in the bottle; however, the bottle must be discarded by the patient because the medication is only stable for 7 days after first opening.”
On the label for CYSTADROPS · DailyMed
“Instruct patients to discard the bottle at the end of 7 days.”
On the label for CYSTADROPS · DailyMed
“After Opening: Record discard date on the bottle, which is 1 week from the day the foil and bottle were opened.”
On the label for CYSTARAN · DailyMed
“Discard 1 week after the foil and bottle were opened even if there is medication left in the bottle.”
On the label for CYSTARAN · DailyMed
“Discard after 1 week of use.”
On the label for CYSTARAN · DailyMed
“There may be medication left in the bottle; however, the bottle must be discarded by the patient because the medication is only stable for 1 week after the foil and bottle were opened.”
On the label for CYSTARAN · DailyMed
How the label says to keep cysteamine
Storage is the other half of the question: the stability behind any date assumes these conditions, and a medicine kept outside them ages faster than the calendar says.
- “16 HOW SUPPLIED/STORAGE AND HANDLING CYSTADROPS (cysteamine ophthalmic solution) 0.”
- “Before First Opening : Before opening, store new, unopened CYSTADROPS in the refrigerator between 36°F to 46°F (2°C to 8°C).”
- “Keep the bottle in the outer carton in order to protect from light.”
- “After First Opening : After opening, store opened CYSTADROPS at room temperature between 68°F to 77°F (20°C to 25°C).”
- “Keep the dropper bottle tightly closed in the outer carton in order to protect from light.”
- “2 Preparation for Administration Patients should be advised to store new unopened CYSTADROPS bottles in the refrigerator in the original carton between 36°F to 46°F (2°C to 8°C).”
- “After first opening, store opened CYSTADROPS at room temperature between 68°F to 77°F (20°C to 25°C).”
- “of Bottles Advise patients to store new unopened bottles in the refrigerator in the original carton.”
Frequently asked questions
Does cysteamine expire?
Two different clocks apply and only one of them is the printed date. The date on a sealed pack is the manufacturer's guarantee for the unopened product. Once it is opened, mixed or diluted, the label imposes its own limit — as tight as 7 days on some cysteamine products, and that is the number quoted on this page.
Can I still use cysteamine after the date on the box?
This page cannot tell you that, and nor can any page. The FDA's own shelf-life programme found 88% of tested lots stayed within specification at least a year past expiry — and concluded in the same breath that lot-to-lot variation means this can only be confirmed by testing each lot. What you can check at home is the in-use limit above and whether the product has been stored as the label requires. Ask a pharmacist about a specific pack; they will also dispose of what you no longer need.
Why do different cysteamine products have different limits?
Because they are different formulations. A suspension that gets mixed with water, a pen that gets carried at room temperature, and a sealed tablet do not behave alike, so each manufacturer's label sets its own limit and each is shown here with the product it belongs to. We never merge them into one number for the molecule.
More on cysteamine
Quoted from FDA labels for reference, not medical advice, and not a suggestion to use anything past its limit. If you are unsure whether a pack is still good, a pharmacist can tell you and can dispose of it safely.