? The Shelf Life of Used and Unused Lantus Pens

Casey Warner

Member Since 2018
I have a Lantus pen that I started using around November 18, 2018 and it probably has anywhere from 20 to 80 units left in it, maybe more. How long can that pen safely be used? Is it good to use until it becomes cloudy and/or I see particles in it? It could last for a couple more months, yes?

What about the unused pens? I took their caps off to check something (the ice pack leaked during shipping), but I never stuck a needle in them. Are those likely to be good until the expiration marked on the pens? I've been storing them in the refrigerator.
 
A pen or vial is considered unopened until punctured with a needle. Some say Lantus can last up to six months, but others say different. I used a vial for two months (stored it perfectly) and when I brought my cat in for a fructosamine test my vet said his numbers were way way higher than the last fructosamine test we did when I was still using the insulin "fresh". So, I don't know. I think if you're home testing and can monitor to see if you notice any difference you can use it as long as it's working.
 
I used my Lantus (and Levemir) cartridges, which are a pen refill not available in the US, to the last drop. For Neko that varied from two weeks to over 90 days, depending on her dose.
 
Thanks.
One of the reasons I was asking is because I have a partially used pen that I don't need anymore and was wondering if my vet's office could donate it to another client who might want/need it. I know they accept donations of some medications, but I don't know how anyone would feel about a used insulin pen. Most of the (free) donated items I've been given have been sealed (like Revolution and Cerenia). I have on two occasions been given tablets that came from other clients.

I'm just not sure if my pen is still good. I'll check with them to see if they want it, but I thought maybe I'd check here about the shelf-life first. I know people here are more knowledgeable about this than at the vet's office.
 
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