Advice on switching from NPH to lantus

Hey all,
I just switched from NPH to Lantus. In general my BG readings have been better, but I’m having trouble with the nuances of Lantus, food, and exercise. For example, I usually exercise after lunch and with NPH I never took insulin before this. The other day (2 days on Lantus) I had lunch…my BS was 300 (ouch - too high - I shoot for 200 before exercise). Took a brisk 4-mile walk, which would usually drop me 100 points. My BS barely moved so I took 2 units of humalog and it went down to about 140.

I guess my main question is how to adjust this new long-acting insulin with my food and exercise at lunch…


Are you bolusing with humalog for your lunch?

Karen…I’m not using a pump; I still do shots. When I was using NPH I didn’t take humalog at lunch…so I’m wondering with Lantus if I need to do that exercise or not…

Thanks for the quick response!


I went from NPH and regular to Lantus and humalog. With NPH I never bolused for lunch either, but Lantus is what they call the poor man’s pump and you have to take humalog every time you eat with a carb to insulin ratio. If you know you are going to exercise then you would decrease your humalog.

With Lantus you really cannot eat without taking humalog

Get a book called “using insulin”. Tell you how to adjust the lantus and humalog. Lantus is a basal insulin and it is not intended to do anything for meals. Usually it is about 50% of you total daily dose of insulin. and it is best split in 2 an am and a pm dose since it does not last exactly 24 hours. Humalog is usually injected on a basis of insulin/carb ratio. The book goes into the fine details.

Basal insulin isn’t used to cover meals. It’s too slow acting. Your Lantus dose is correct if your BG is at target for fasting & between meals (with no rapid acting on board). That’s the role of basal. Like everything, it’s trial & error to get doses right.

Lantus is not as stable as pharm literature & doctors state. It does peak. I had persistent afternoon lows with Lantus even after changing doses & taking split doses. I’ve had far better control using Levemir. Levemir doesn’t sting because it’s not acidic like Lantus. Another advantage of Levemir is that it doesn’t lose potency as quickly as Lantus. I found Lantus becoming less effective at day 26 & a goner by the 28th day. I use a vial of Levemir for 6-8 weeks, usually 8 weeks.

It shows how strong NPH is. It acts more like a small unit of regular that is always present. Actually NPH is - it is just regular bound to protein to deactivate it. The release rate from the protein is very uneven. That makes it so hard to live with NPH: your life is in a cage of musts. Now with a modern basal insulin you should have much more freedom. But as Karen wrote there is no free lunch anymore. I scratch my head: your doctor has not prepared you for these big differences?

When I got my pump, I transitioned directly from R/NPH. The doctor told me that NPH has only a 53% chance of peaking when it is supposed to so it can (or did in my case…) cause fluctuations in your BG to which you react which, in turn can cause more fluctuations? I don’t think that Lantus is supposed to have the same degree of peakiness but people like Gerri have observed peaks that, nonetheless, can cause the same sort of problems? I agree with Karen and Holger though that it would be more useful to cover lunch with a dose of 'log, even a small dose if you are able to exercise regularly?

Without knowing the timing of your NPH and new Lantus regime, it is kinda hard to know. What I would suggest to you is that first, NPH peaks in 4-9 hours, so if you normally took it in the morning, then it would be peaking at lunch. Lantus is much flatter. If you are comparing equal doses of NPH and Lantus taken first thing in the morning, your observation would not be surprising.

Second, you shoud remember that NPH and Lantus are different insulins with potentially very different absorptions, you may find that your proper basal dose of Lantus not the same as your NPH dose.

And finally, if you have not started to bolus for meals, you may find that is necessary. You might have been able to “muddle” through using the NPH peak to “cover” lunch, but Lantus is flat, I doubt you will be very successful covering meals with any amount of carbs using Lantus (unless of course you still have a happy pancreas).

Hope that helps.

ps. Do not attempt to exercise when your blood sugar > 250 mg/dl. You didn’t have enough insulin on board to cover your meal and without insulin on board, attempts to use exercise to further reduce your blood sugar would not work (and in fact may make it higher).

pps. I would actually suggest for a lunch and exercise regime, a bolus to cover the lunch is the way to go. It is best to start exercise having eating and bolused to cover the carbs.

Thanks for all the helpful replies! The change in after-exercise numbers threw me. I didn’t expect that…so now I’ll just play around with tweaking a lunch dose that works with exercise!

I agree that you probably need a short acting insulin as well…humalog, novolog, or apidra. Most T1’s do.
You will notice that Lantus does not really cover your meals, it is not intended to, but it also will keep you much more stable than NPH.

Perhaps I’m misunderstanding your questions, Lora, and I’m sorry if so. But when you refer to “tweaking a lunch dose that works with exercise” do you mean you are also on a short acting insulin such as apidra, humalog or novalog? If not, you probably need to be. As others have said, Lantus is not meant for meals and exercise. It is a long-acting insulin that acts as a background insulin to provide a small amount of insulin all the time. Then you need a spurt of fast acting insulin for meals. This replecates what a healthy pancreas does on its own. Your response that you “are not on a pump” when asked about bolus means you might not understand the idea of MDIs which are a bolus/basal regimen similar to a pump. Lantus is taken once or twice a day, often first thing in the morning and at bedtime. It isn’t something you would give at meals. I recommend you get a copy of Using Insulin.

I had such a drop with NPH I was surprised by the opposite with Lantus…and the humalog I take is tiny…it used to be 1 or 2 units at most with dinner and 1 with breakfast. None with lunch if I exercised. I’ve been much happier with my overall BGs in the last few days, I guess I just need to slowly experiment with the humalog at lunch, exercise or no exercise. I love my doc…but sometimes I think he thinks I know more than I do and forgets to give me details.

Thanks for the reference. My mom used to split her lantus does, but so far the one shot seems pretty good so I’m going to work on the mealtime stuff first!

Thanks for the levemir info…I tossed that out as an option as well…but I’ll see how the lantus does…so far better - other than the lunch time thing!

Thanks BCS! I do lantus at 9 pm right now. I’ve had really good luck with stuff so far. My last A1C led to this change, so I think I got lazy in looking up info. My mom was and my step dad is on lantus, so I sort of understood the action, but not necessarily my individual response to it.

I get a little wigged out about lows when I exercise by myself (walking in a cemetery usually). I guess it’s just going to be a new round of experimentation - one that requires me to remember my cell phone on walks for awhile!

Using the “non-peaking” Lantus will require you to use a fast acting insulin with lunch, using a insulin to carb ratio. As others have said, the NPH was peaking before and actually covering the lunch. Then, exercising while it was peaking most likely increased it’s effectiveness even more. You actually have two challenges. Finding an insulin to carb ratio for lunch (your dr should be able to get you in the right ballpark) and then, discovering how many carbs you need before your walk. Then, you can put it all together into a wonderful blood sugar, insulin, carb story problem.

It might seem like a lot, but I really think you will find more freedom and better control with these insulins. Good Luck!

Glad it’s working, Lora. Big adjustment from what you’ve been using. I mentioned the possiblity of Lantus peaks & lows because docs don’t tell us this. They believe it’s smooth & level.

Nothing about D is smooth and level, no matter what your choice of insulin is.