Forgetting to take Lantus?


I disagree. I see no magic expiration and change in effectiveness after 28 days. I don’t refrigerate it and keep it in house ambient temperature. It actually lasts much longer for me. Where does this statement originate. Some folks are challenged with the high cost of Lantus, as with other insulins, and discarding it may not be necessary. I would confirm with other sources before taking this statement at face value. It has been repeated by the same source at this site, not by any other users.


The large dose is about 24 hrs. based on the time of absorption for the larger volume. Splitting the dose, will result in a shorter absorption time span and is the reason it works for those of us who forget the one bulk daily shot.

I wondered why the early recommendation was to take one injection before bedtime, when that is the time you would have no chance to correct–you are asleep. I have split the dose from the start with Lantus, when it was first released. I would like to see another solution in the future. I believe the fast acting is a challenge for some of us. Humalog takes time to bring down a high BG, but is quick to lower your BG other times. It is a challenge to time it all right. Lantus in the background is great compared to the old NPH.


I have never seen insulin “spoil”. It does have preservatives to prevent this.

It can gradually lose it effectiveness, but that doesn’t magically happen on day 28 or 29. It diminishes gradually. The company that makes it will not guarantee it after 28 days, but that doesn’t mean it will suddenly become totally ineffective. When I first started insulin and was on a substantially lower dose, I often had a penfil cartridge open for longer than a month with no loss of effectiveness. I don’t recommend it, but I’ve done it and know lots of other people who have too.

Conditions in the room you keep it in also have an impact. If its fairly cool where you keep it, then it will probably be more effective than insulin stored in a warmer location.

Insulin that is subjected to high temperatures or freezing temps is ruined.

If you have insurance I recommend opening a fresh vial after the 4 weeks are up. If you don’t, and money is tight, you could try going longer and closely monitoring your numbers to see if its still working well, but talk to your doctor about programs for those on a low income. Some manufacturers will help out in situations like that.


Ok OK! ... I will TRY and explain the problem, but it can get a bit complicated, ie harder than READING the drug info sheet that comes with EVERY Rx of Lantus.

The 28 days is stated clearly with every vial/cartridge/pen of Lantus, Does anyone bother reading the info sheets that come with Lantus, Humalog and/or ALL their other Rxs?

The HUMAN element....... Every diabetic is different. Some have some reserve natural insulin/beta cell capacity (some DO NOT) . IF you are one of these LUCKY diabetics, then a slight decline in Lantus potency may have less of an immediate effect. Your beta cells may have recouperated some durring the time the Lantus was a full strength. In THAT case you MAY be able to use a vial (etc) Lantus an extra day or even a couple days beyond the 28 days. USING Lantus BEYOND 28 DAYS for many can be RISKY, even life threatening!

For most type-1s, you can get into TROUBLE very quickly and risk possable DKA. Using an OPEN container of Lantus beyond 28 days can lead to not only complications, DKA or even a very expensive ER visit or hospitalization! Very few type-1s have ANY reserve beta cell function to compensate for the weakening Lantus. Some that do have a little reserve, some may be able to get an extra day, others may get 2 or even 3 extra days.

For ME. I noticed via my glucometer logs a trend/change when I try using a vial past the 28 day mark. There are time I hae a little LIMITED natural beta cell capacity, and there are time I have NOTHING.

I have tried, with some success adjusting my Lantus dose to compensate. I usually get away with it, BUT, I DO NOT RECOMEND THIS TO ANYONE!

Bottom line. use your Lantus past the 29 day mark AT YOUR OWN RISK!

Does this HELP anyone here understand the situation and WHY one person can seemingly get away with it and another diabetic CAN NOT? I said seemingly because doing this is RISKY and the piper may collect on this at a later date down the line.



Well from my experiences from having to take insulin I have forgot the Lantus a lot within 5 ish months Of having diabetes and I was fine to camp it out till the next night. Allyou have to do is watch the blood sugar and I know it’s not good to miss this shot.


I personally take lantus at around 9pm. I’ve only skipped it by accident once, but I have taken it a few hours late a couple times. What do you do when that happens? Do you just take it at the same time the next day?


Hi all. I did forget to take my lantus (16) inits last night and woke up today at 302. I have called my endo and his office is closed. Plz help! Do I take a shorter dose or lantus now (8:15 am) or just correct humalog ? If I do take lantus now , how much ?
Help and thanks !


@Ivan_Castro. Personally, that many hours later I’d just correct with my fast-acting during the day today and then take the normal dose of Lantus at night.


Thank you :slight_smile:


Hi Janice,
I think my case is pretty much more complex because I can’t remember whether I have taken my night long acting shot or not!!!
My FBS is 160 mg/dl.
Do you know what I am supposed to do?