STUPID Mistake :(

There are days when I just HATE having type 1, and today is one of them. Yes, I made yet another stupid mistake. :(

Here's the situation: I was drinking a cup of coffee when I realized the time and that I hadn't taken my dose of Lantus. At my last doctor's appointment, I decided to switch from the Lantus pen to the vial in order to save money. I reuse syringes, and I keep the current Lantus syringe in a dresser drawer in my room so it does not get mixed up with the syringe I use for Humalog (which is in my meter case). So, off I trot to the bedroom, getting my syringe, go into the kitchen to get the Lantus, which is in the butter compartment, away from the Humalog (which is behind the yogurt).

I sit down, load up the syringe with 5 units, and inject into my leg -- my preferred spot for Lantus. I return to the kitchen to put the vial back in the fridge when I notice that.....

I'm putting the box behind the yogurt AND the vial of Lantus is still sitting in its spot in the butter compartment!! :(

ARGH!! Damn it, but I feel stupid at this point!! FRACK!!

So, I do the calculations and start the eating. After all, 5 units of Humalog is A LOT. I make two slices of toast (regular white bread, 30g), two tablespoons of "all fruit" jam (18g), and then chug 6 ounces of grape juice (30g). Total additional carbs eaten for this mistake: 78g -- so far. I may need another 13-17 (ARGH!!) but...

Anyone know what the implication of having Humalog in a syringe that had Lantus in it at one time is? Could that impact the effect of the Humalog in a way? Inquiring minds need to know!

Hey AngelaC
I don't think there is any worry about using the same syringe - the cross contamination would be tiny (though this is just my opinion, not an expert!)

I think most of us have made similar mistakes (you'll find other posts like yours - if you want to read about others experiences)... and it's not stupid! just a mistake, hopefully one time

Keep testing... and stay near a good supply of food, hope all works it self through quick and without any low troubles

I did a test about 1/2 hr ago -- about an hour after I had my mistake and went on my eating binge. I was 173 at that time, so apparently, I did eat enough. Unless that was simply some leftover jam that was on my hands.

It does specifically say in the Lantus literature not to mix Lantus in the same syringe as any other insulin, including using the same syringe that might have hand another insulin in it. It can make the Lantus not work anymore. I don't know if the same is true in reverse with Humalog. It may be in the Humalog literature, I don't know. I keep my two different kinds of insulins in a cosmetic pouch that has two separate zippered compartments. I use the Humalog pen and the Lantus goes in with a syringe. I'm not like to mix the two of them up because they require two different delivery methods. Prior to using the quick pen for Humalog, I did confuse insulins a before. A couple of times was enough to make sure I never do it again.

I don't know actually if you should keep either lantus or humalog in the fridge. In fact it says on the package once it is open you should keep it at room temperature. But I did exactly the same thing you did last month, took 15 units of humalog instead of lantus. Since I am fairly insulin resistant in the morning it was not such a huge deal, I just had to consume a bagel and it pretty much took care of it. My blood sugar didn't go above 148 or below 97 so over all while it was a stupid mistake it was one that didn't have huge implications, and probably one I won't repeat. And although they also say don't mix lantus and humalog there are a few studies that say it is no big deal. It's probably just the drug companies way of making us use more syringes.

i kind of had to chuckle at your description, behind the yogurt, in the butter compartment! i was a freak about this happening when my son was on MDI i even colored in the boxes purple and orange in the butter compartment and in the back of the fridge! and low and behold i did it not once but twice, pig out fest for my 11 year old at the time i felt terrible to say the least!! so glad he is on a pump now but i still wake in a panic at night thinking did i???? oh yeah we did his bolus for snack ..... no more lantus.... he needed to eat about 120 carbs to cover his "lantus' when i messed up. syringes are pretty cheap, i guess we have good insurance because i never would of considered reusing but i guess it is not a biggy as long as it doesnt dull up. best of luck we have probably all done it. only another D good get the dread, horror, what did i do and then hopefully laugh and forgive ourselves after. life is to short to beat ourselves up for our errors. blessings! amy

According to the company's website it should NOT be combined with anything else

Destroy the syringe and get a brand new one. The chemistry involved you got me...

The STUPID is if you let it happen a second, third, forth time. Once, don't do so again ; )

The pH of Lantus is approximately 4.0. Most other insulin injections run a pH around 7.2 to 7.7. Mixing lantus with novolog, nph, etc offsets the pKa of lantus making the duration (18-23 hours) variable and unstable. But the thing is, this involves actually drawing up 2 kinds of insulins and mixing them in to one syrings. It does not really get in to the pharmacokinetics of a microliter of lantus coming in contact with a microliter if humalog on the way through a 32 gauge needle. But at least from a chemical standpoint it gives an answer to why they should not be mixed.

However: This paper debunks that myth somewhat and was in Journal of Pediatrics 2006. At least in children it was found there was no statistical significance between the blood sugar control of the group that had mixed insulins and the group that didn't. It wasn't a huge patient population, probably because it was kids, and what parent wants their child to be a guinea pig ?
Mixing rapid-acting insulin analogues with insulin glargine in children with type 1 diabetes mellitus.

Fiallo-Scharer R, Horner B, McFann K, Walravens P, Chase HP.


Barbara Davis Center for Childhood Diabetes, University of Colorado Health Sciences Center, Denver, Colorado, USA.



To determine whether mixing insulin glargine (IG) with a rapid-acting insulin (RAI) analogue in the same syringe had any deleterious effects on glycemic control in children with type 1 diabetes mellitus.


Data from 55 children mixing the IG with a RAI analogue was collected for 6 months before and 6 months after the insulin mixing began. Data from a control group of 55 children not mixing the insulins was collected at similar intervals. Parameters evaluated included hemoglobin A1c (HbA1c) values, number of non-severe and severe hypoglycemic events, number of diabetic ketoacidosis (DKA) events, and blood glucose distribution patterns.


After 6 months of study, HbA1c values were equivalent for the control and test groups (8.54+/-1.14 vs 8.61+/-1.14, respectively; P=1.0000). Percentages of blood glucose values in, above, and below the target range did not vary significantly in the groups. There were no significant differences in the groups in the occurrence of non-severe or severe hypoglycemic events or of DKA events.


There were no significant differences in glycemic control between children who mixed IG in the same syringe with a RAI analogue compared with children who took separate injections. This article also demonstrated that there was no statistical significant difference between the 2 groups of patients. And yes again it was children and again it was not a huge patient population.

Thanks for the interesting information Clare! I'd wonder if children are the best test group for something like that, due to the sort of craziness a lot of parents report? I'd be intrigued to see a test of adults with relatively tight control to see if it'd upset their applecarts.

I don't have that issue as I only use one kind of insulin but, after the initial freakout from that sort of mixup, I'd probably try to arrange some sort of greasy junk food as 1) I love greasy junk food and 2) I think the fat/ protein combo would smooth things out for awhile.

I've done that before--used a lantus syringe to take a correction for novolog. It didn't make any difference with the novolog, but I noticed (after the fact) and didn't use that syringe again for lantus because the mixing messes up the action of the lantus, not anything else.

Hi AR, I think the reason they might have used children is MDI is probably hardest on little kids, and if parents can avoid a couple of shots a day by mixing lantus/humalog or lantus/novalog then I'm sure most parents would prefer not to stick their kids the extra times. Us adults they probably couldn't give a rats' ■■■, but I think the reason most of this research is not in the readily available in the public domain is it would cost Becton Dickinson money for all the pen needles and syringes that would not have to be used. JMHO, but I am getting super cynical these days especially about big pharma.

Well, to me, it seems like if you want to find something out, you'd want "test pilots" who are "pushing the envelope" with very tight control, so that if there were an effect from syringe mixing or whatever else you were studying, it would be apparent and, unless they are airheads (*cough cough*), they'd be able to explain their conclusions to the researchers. It seems like a lot of times with kids, it's more like a slot machine than something from which a scientist could get a lot of useful data from? Not that the kids and their parents are doing a bad job, but the process of monitoring doses seems to be complicate by growth and development. Or at least that's my totally unresearched theory, based mostly on reading message board posts...

I guess then the point is they don't necessarily want to find this out. Not only are there only 2 papers on the subject, but both those papers use children as their "test pilots" and while I agree it is definitely more of a slot machine approach, my thought is some parent must have funded the research because there is absolutely no reason for Sanofi Aventis, Becton Dickinson, Eli Lily or Novo Nordisk to fund research that would ultimately lead to people using less of their products or using their product in tandem with a competing companies' product. That is of course my totally unresearched theory as well.

Hi Angela, don't feel bad as many MDI'ers have done similar things.

To me, I would err on the side of caution and throw out the syringe. I would not use that syringe in your Lantus. My endo told me that if you get even a drop of short acting insulin in your vial of Lantus, it will make your Lantus act as short acting insulin instead of long acting insulin.

I wouldn't want to do that experiment.