How long is Latanoprost stable at room temperature after opening?

• A. Cold storage only.
• B. 2 weeks at room temperature.
• C. 12 weeks at room temperature.
• D. Room temperature for 6 weeks.

Answer: (D)

Opened latanoprost eye drops remain stable at room temperature for about six weeks. This means the medication is expected to keep its potency for roughly six weeks once the bottle has been opened, as long as it’s stored at typical room conditions, away from direct light, and the bottle is kept tightly closed. After about six weeks, potency may decline and the risk of contamination increases, so the product should be discarded. Cold storage after opening isn’t required, and the longer 12-week timeframe would exceed validated stability, while 2 weeks is shorter than the supported period. Pharmacists often advise patients to note the opening date and discard the bottle after six weeks.