Splitting Lantus Dose? Crazy BS Numbers

I have read a lot on here about splitting Lantus, instead of taking one shot. I’m contemplating, but wanted some more opinions.

For the past 2 weeks I’ve had awful BS problems! Up until then, I was doing great and have had no real issues really. I had one bad night at the start a couple weeks ago, around the time of my menstrual cycle, where I could not keep my BS levels up. I had consumed so many carbs over the course of 4 hours (this was after taking my normal 15u of Lantus) and within a half hour I would drop back down significantly. I almost went to the ER because I would eat 15g of carbs, it would take my BS up in 15 min. but a half hour later I would plummet.
Example: First low was 75. 15 min. later after drinking a small can of soda, I was 45.
I ate some candy and a small juice box, got it to 130, 30 min later, 100. Which I didn’t feel comfortable going to bed with. This was on and off throughout this time, even after eating so much.
I finally got it up to above 150 and went to bed. Woke up high, of course, but that night was terrifying to me, and I still can’t explain it other than hormones.

Usually by this time hormone fluctuations would be gone. But taking my normal 15 u. of Lantus at night and even knocking it down to 14 u. I was having too many night time lows! I used 14u. for a couple of days, and really paid attention to carb counting and correction doses, but it wasn’t working. So I switched to 13 u. last night.

I am using 1 unit per 10 carbs (tried 15 carbs, it wasn’t enough), and 1 unit to drop me about 75 pts. at times, even 100 pts. where as before all of this, a corrective dose would = 1 unit, per 50 pt. drop.

I can’t explain my big drops (as in my corrective dose having to be altered so much). I also can’t explain my highs: I’ve never had major spikes like this, even after correctly carb counting, and I’m talking, shooting up to 300.
The past couple of days I haven’t had lows, but I’ve been taking 13 u. of Lantus. However, I’ve been dealing with too many highs. When I correct, it still is only taking me 1u. of Novolog to bring me down significantly. Should I give the 13 u. some time to work?

Being high for so many days from being up and down, to fearing lows, to trying to get it figured out, is just so dang exhausting! Today has been a little better, but still no where near normal like I was before all of this.

So about the split: if you split your Lantus dose, when did you start? How did you split? If I were to try it, would I just take a normal night dose say tonight, then tomorrow night do half and then half the next morning?

I appreciate all the help! I have been really struggling and am trying my best to not roller coaster too much! My insurance no longer covers Lantus so I have been picking up scripts of Tresiba. I haven’t started it yet though, until the Lantus is used up because I don’t want to waste, and want plenty of insulin just in case we lose insurance. I’ve read nothing but good about it, and I’m hoping when I’m done with Lantus I will do well on Tresiba!

Hi Daisy707,

In my experience, with is significantly less than some around here, Lantus can effectively be split into 2 doses. I used to do it with morning meal and 12 hours later - 1/2 doses at each. You should contact your Endo or CDE to help you calculate/recalculate your Basal and Bolus rates - they are unique to every person. Basal adjustments should be done slowly, over time unless a medical professional tells you otherwise. Menstrual cycles will significantly affect bgs for some women, and there are many entries on this blog about the subject. You will probably enjoy Tresiba much more than Lantus. I for one will only go back kicking and screaming. I am hopelessly in love with Tresiba and my bgs are the best they have ever been.

I hope you find the source of your fluctuations, it’s nerve wracking and very scary to not know why. I, like many here will have stellar bgs for an extended time, only to have everything go sideways for a short time. Personally, and understand I am not a doctor, I cut back on my Basal and try to stabilize everything with my Bolus. Generally when this happens my I:C ratios are very different than normal also, so I tend to take a conservative bolus with adjustments as needed after 21/2-3 hours to I don’t have a huge stack.

Hope this helps and doesn’t confuse things.

1 Like

I do a split dose. I take half in the morning and then half at dinner time. I was finding that Lantus didn’t work a 24 full hours for me. It faded out after 20 hours so it was literally leaving me with no coverage for four hours a day at a very bad time of day. So the decision was made to split it and see what happens. It has worked well for me. I made the switch about 8 years ago so my memory is a little foggy as to how I made the transition. It obviously wasn’t a big deal or I would remember it better. I think the way to start is to take half the dose at your next scheduled time and then plan to take the second half approximately 12 hours later. Cover any shortfall with a little extra regular or whatever you use for quicker acting. You might find that the split isn’t a true split of what you are taking now. I think I started off with a split but then found that I needed to up each half a couple of units.

1 Like

Thank you so much!! I definitely contact my doc if I make major changes, but last time I saw her she said adjusting a couple units here and there is fine. So I’m sticking with 13u. of Lantus again tonight and re-calculating my Novolog for meals as needed. If I need to correct after a meal I will. I’ll give it a few days to see if the change is working, if not I’ll contact my doc to see what I should do. You didn’t confuse me at all; good to know I’m on the right track at figuring it out! :slight_smile: and I am hoping I will like Tresiba as well!

Thanks for the reply! I haven’t noticed Lantus not working 24hrs on me, but the lows at night have been an issue. I’m sticking with my 13u. a few more days to see if that helps, if not I’ll contact my doc about splitting and at least giving it a try! At least seeing that it works for more people than not, gives me some hope that I’m not out of options :slight_smile:

When I took Lantus, I didn’t split the dose at first, but eventually did split it. It had a major improvement on my blood sugars.

Menstrual flucatuations can be very hard! My basal rates just jumped up by 50% overnight due to hormones. Not only are the changes so extrme, but they are sudden yet also variable, and that makes them very hard to deal with.

1 Like

I might be asking about it soon then! And yes it does make it very difficult at times! Sometimes I have to increase my basal as well; this past time I had to decrease it a ton. It really wears me out.

If Lantus does work 24 hours and you are having lows overnight you might consider taking your Lantus in the morning. The other aspect of a split dose is that the two injections don’t have to be the same, you can make one bigger and the other smaller to allow a bit of adjustment in your overall basal profile.


Lantus only works about 20 hours for me, so when I was on it, I did two doses, unevenly split so that I had more in my overnight dose. That said, Tresiba is much better than even split-dosed Lantus.

I would just start as you suggested with half and then half one day, knowing you might have a day when you’re running a bit high while it catches up, and compensating as needed with short-acting corrections.

1 Like

Well, 13u. wasn’t cutting it for me. I was having way too many highs. ugh. I’m back to 15 u. of Lantus at night, because I think the dropping low issue is gone. Now, fighting to get it back under control without lows, but without spikes. I’m trying to figure out my carb ratio too because with some things my counting works, others it doesn’t and I spike too high. We’ll see. I’m guessing my next A1C isn’t going to be the best, but what can you do. :nerd: