Lantus Humalog Why not mix?

I have been on MDI for 37 years, well really DI for about the first 20 or so and MDI for the last 17. I have always been told never to mix lantus insulin with humalog. So as a result for the last 5 years I have been taking at least 5 and some times more than 5 injections every single day. If I could mix lantus and humalog then I would save myself 2 shots a day, something I would truly appreciate. Not only would it save me injections, but it would also save me syringes and waste. So I found these 2 papers online. One was published in 2006 in the Journal Pediatrics and the other was published in Diabetes Care Journal affiliated with the ADA. Both used children as their test subjects and neither found any statistical differences between the groups that mixed lantus and humalog and those that did not. One study used CGMS data to discern blood sugar fluctuations etc. So my question is why not mix ? It would save at least 2 injections for me every day. It would save 2 syringes and the trash. Are we just scared in to not mixing by the insulin producers ? Or the syringe makers ? I know it is not a huge patient population that was used. But there were 110 patients in the first study and no statistical differences. I think the next time I see the endo, I'll get a script for a vial of each and start mixing. Do my own study.

It has to do with the way Lantus chemically operates. Lantus is soluble (i.e. dissolves) in an acid solution. In a neutral solution, it precipitates out into crystals. That is what happens when you inject it - the acid solution in the vial or pen is neutralized by your body and small crystals form under the skin. These crystals dissolve slowly over time to give Lantus its slow action.

I think they are afraid that if you mix and re-inject humalog, for instance, into the Lantus bottle, you will change its pH and make it less acid. This could cause precipitation and formation of crystals in the vial. Next time you inject, the concentration of the Lantus would vary depending on how many crystals you pick up in the syringe. It will make it more variable.

This is analogous to but not the same as the reason with the old R and NPH insulins . you are instructed never to let NPH get into the R bottle. It will slow the action of the R by causing insulin to form a complex with the protamine.

By the way, the acidity of Lantus is why it burns when you inject it.

Perhaps it may work if you manage not to re-inject stuff intpo the Lantus vial and it is only mixed in the syringe, but frankly diabetes is variable enough that I am not going to take chances to save an 11 cent (retail) syringe. A trip to the ER would waste far more money than thousands of syringes.

Similarly, contaminating an expensive vial of Lantus would waste more money than thousands of syringes.

I know that papers, I read them for the same reason as yours ;-) and tried. Reality is that mixed they sting more than lantus alone, and humalog becomes way slower so you get higher BG after meals.
Levemir is a little better to mix, but it slows down a lot the fast insulin.
So I stopped experimenting and prefer to use pen instead of syrings and do 2 shots.

To try you don't need a vyal, you can take insulin with the syring from pen or cartridge. First you take lantus/levemir, only after you take the fast insulin just to avoid to put something in tha lantus cartridge.

And yet in the "olden" days I used to mix lente and regular insulins routinely without contaminating either one. In fact there are tutorials online teaching proper technique for mixing insulins in the same syringe. While I understand the mechanism of action of lantus and I am taking this entirely in to my own hands, I am also not that variable or worried about trips to the ER from doing something that parents did for 6 months without issue. I'm sure they were trained on the proper technique to mix insulins and not contaminate one with the other. But to each his own.

See and Lantus for me does not sting, but that is just me. But I am really happy that someone actually has some first hand experience with this. That is the reason I asked the question in the first place so thank you for your response.

Pretty much what HPN posted. If carefully done so as to ensure that no cross contamination occurred one may even accomplish and achieve results similar to the studies cited. However, given the nature the "general" public the Sanofi can't take the chance that someone somewhere will mess up . . contaminate their Humalog/Novolog and being sued. I'm quite sure when someone complains about their Lantus or fast acting not working the first few questions deal with the possibility of the patient mixing insulins.

The "general" public at large is such that manufactures of appliances typically used in the bathroom not to use them in the tub/shower. Explicit warnings in the instructions. Sanofi has done no less with Lantus.

I think what kiva posted is the real reason the package insert reads the way it does - the manufacturer worry about liability.

However I can think of 2 other reasons it may be less desirable for some people:

1) It means you have both the long acting and short acting vials in front of you at once and increases the chance that someone might make a mistake and reverse the amounts of the two insulins and end up with a large dose of short acting and a small dose of the long-acting. A meticulous person might never do it, but we do read about people on here tired or in a hurry that accidentally swap the two, even with keeping them in different places. It might happen easier if you are using both at once.

2) Bernstein thinks that large doses of insulin subq are absorbed slower than small doses...mixing the two means you have a fairly large bolus in one place.

Again, it might work out just fine with someone that is meticulous. But as someone trained in aviation, I am always looking for ways to eliminate unnecessary risks, so if I were back on MDI, I wouldn't do it. But that's just me.

Back in the days of regular and NPH, the docs warned me that if I "premix" them, they don't turn out the same as two separate doses, the NPH ends up "stretching" the regular, and the regular ends up speeding up the NPH.

Of course they also sell 70/30 (or is it 30/70?) NPH and regular premixed at the pharmacy!!! So I'm unclear on how much of this is folklore and how much is reality.

Others commented on Lantus stinging... yes large doses do but for me smaller doses don't. I end up splitting (to get 24 hour coverage) my 20 units total of Lantus into two shots of 10, and I rarely have the stinging with a shot of 10, but back when I did 20 all at once (did for a little while) I had it kinda often.

I think there are advantages to many smaller shots rather than a few large ones. Even when I was doing MDI back in the Regular and NPH days, it was clearly better for me, to have more smaller shots, than a few large ones. More predictability in terms of absorption for sure.

Speaking of 70/30 pre-mix - can someone explain to me why this is a good insulin regimen ? You can't independently control basal and bolus insulin...sounds like it might be harder to get tight control.

I have done the old swap and misdose myself! I am very careful too! I used to get up at 5 A.M. and take my Lantus and one morning I took Humalog, it was not good. Now I keep the two insulins in seperate areas of the fridge, I NEVER have them both out at the same time! Sometimes the Lantus does cause a little sting but most the time it dosen't. I would rather take them seperate that way I know that I am taking the right one and the right amounts. I used to take NPH and when I would take my breakfast shot I used to mix that with Humalog. My Dr told me never to do that with Lantus. I would consult your Dr first before you start doing stuff like mixing. Good Luck to you!

I take 24 in the A.M. most the time it does not sting, but oh this morning it was horrible! My arm felt like it was on fire for a couple minutes! OUCH!

Thanks for this info! I have always wondered why you shouldn't mix them. I used to take NPH and was able to mix that with Humalog for my breakfast shot. But it really didnt' change anything I still had to take at least four shots a day because I took NPH at bedtime too.

The basal/bolus routine with flexible dosing and eating is a relatively a new concept to diabetes management. Back in the day with animal insulins and with the human insulins, fixed dosing and eating was the norm. You ate fixed amounts at each meal and time during the day injecting fixed amounts of insulin at the same times every day. There wasn't any flexibility as there is today. Better insulins and home metering made the current basal/bolus protocol possible.

70/30 is a prepacked marketing product. A lot of people mixed R and N in a syringe so they produced premixed as an option. There was also a 50/50 and 75/25 . . there may have been others.

I haven't read the other posts, so sorry if this is repeated somewhere...
My 3 yr old takes lantus/humalog and the Alberta Children's Hospital was one of the areas where the study was taking place.(our clinic is out of there) They found that if mixed correctly (humalog first, then lantus) and injected immediately following mixing, that there is no adverse effects. It is fine, the problem comes if they are mixed and then sit combined in a syringe for too long, they begin to crystalize. We mix them and have good numbers, never an issue as far as this goes. They do it at their hospital routinely. I would say if you want to, go ahead and mix. Just make sure you do your injection right away.

Thanks Jen, I have heard conflicting replies to my original post, so it is great to hear it from someone who actually does this without incident. I am definitely going to start doing this especially in the mornings as I take both types of insulin before breakfast and it will be at least one less shot. I'm not sure about the night time because I usually take Lantus at 9 pm but I may just switch it around a bit and move it to 7 pm and just take them both before dinner. I'm beginning to like this plan. Thanks again.

Hi Clare. Please be careful and test often when you first start mixing the two insulins.

I sometimes mix my Regular and Apidra in small amounts. Together, they are less effective on peaks after eating and have a longer tail than with Apidra alone; better on the peak than with Regular alone. This works for me for meals with few carbs, such as salad and meat/chicken. With a dessert, no mixing. I take Levemir for basal; no mixing.

If I were you, I'd experiment first with the morning shot and use that knowledge to decide whether or not you want to mix with the evening shot; and if so, how much of each type of insulin to use. The first time you mix in the evening, if you decide to do so, I'd suggest setting your alarm for approx. 2:00 AM to test.

Hi Trudy,
Thanks, I will of course do this experiment with a lot of testing. As I thought about Jen's response, I realize a 3 year old takes significantly less insulin than I do so it will take some tweaking to get it right, but it is something I think is worth experimenting with especially since it has been done successfully numerous times and my own personal opinion is that the only reason we are told not to mix insulins is that Eli Lily, Novo Nordisk, Sanofi Aventis and Becton Dickinson all say not to. But as they are all competing for their piece of the diabetic pie,I am not inclined to take their word for it.

I suspect that there are a lot of variables involved with the mixing, such as amounts of each type, how each individual reacts, and on and on, so I can understand why those who make insulin would be hesitant to recommend it. Those of us here on TuD have the advantage of understanding how to experiment safely. Good luck!

I agree what you say and previous comments about legal issues. Trials for insulins approval never contemplate tests on mixed insulins: it would cost, with no advantage for the company.
It's true the profile action of mixed insulins is a little unpredictable.
But we are type 1, we are accustomed to managing unpredictable things.
(sorry for my english, I hope I expressed well enough my feeling)

Your English is fine, and I think you expressed your feelings well. I agree if there is no profit in it for the company there is no incentive to try it regardless of how beneficial it may be for the patient. But then again when we experiment on ourselves, the only person we are likely to harm is ourselves. And if the experiment is a success or failure we can post on here what we did, how we did it, and what the results were. That is one of the things I really appreciate about TuD.