Does cefoxitin expire?
The printed date covers the sealed pack. Once cefoxitin is opened, mixed or diluted, its label sets a second and usually much shorter limit — quoted below, per product.
Shortest limit on any cefoxitin label: 4 hours
“Discard any unused portion after 4 HOURS .”
That applies to the product it is printed on, not to every form of cefoxitin — check which one you have against the list below.
What the labels say
“Discard any unused portion after 4 HOURS .”
On the label for Cefoxitin · DailyMed
“The entire contents of the bag must be used within 4 hours from the time of initial entry.”
On the label for Cefoxitin · DailyMed
“Note: Following reconstitution (activation), product must be used within 12 hours if stored at room temperature or within 7 days if stored under refrigeration.”
On the label for Cefoxitin and Dextrose · DailyMed
“When diluted according to the instructions above, cefoxitin is stable for 18 hours at room temperature or for 48 hours if stored under refrigeration (5°C or 41°F).”
On the label for Cefoxitin · DailyMed
“The product must then be used within 7 days, but not beyond the labeled expiration date.”
On the label for Cefoxitin and Dextrose · DailyMed
How the label says to keep cefoxitin
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.
- “Special storage instructions: CEFOXITIN FOR INJECTION, USP in the dry state should be stored between 2° to 25°C (36° to 77°F).”
- “The dry material as well as solutions tend to darken, depending on storage conditions; product potency, however, is not adversely affected.”
- “Conditions Store dry powder between 2° to 25°C (36° to 77°F).”
- “Special storage instructions Cefoxitin for Injection, USP in the dry state should be stored between 2º to 25ºC (36º to 77ºF).”
- “Special storage instructions Cefoxitin for Injection in the dry state should be stored between 2º to 25°C (36º to 77°F).”
- “Store the unactivated unit at 20-25°C (68-77°F).”
- “As with other cephalosporins, reconstituted Cefoxitin for Injection and Dextrose Injection tends to darken depending on storage conditions, within the stated recommendations.”
- “• To avoid inadvertent activation, DUPLEX® Container should remain in the folded position until activation is intended.”
Frequently asked questions
Does cefoxitin 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 4 hours on some cefoxitin products, and that is the number quoted on this page.
Can I still use cefoxitin 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 cefoxitin 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 cefoxitin
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.