A rant on ... The Switch (Humalog to Novo)

I know it’s been awhile, but I have been focused on my upcoming cross-country pedaling adventure - see Two Traveling Trikes for more on that.

One of the monkey wrenches that has been thrown into my planning is my wonderful and awesome (NOT!) PBM, Caremark, decided to throw Humalog off their formulary, and mandated that I go to Novolog. Now I have nothing against Novo, I’ve just never used it and I have a really good feel for how Humalog works. In spite of having a pretty good backup supply of MY preferred normoglycemic elixir, I decided that I should try Novo out and figure out its quirks.

So can you believe this? My very first vial was bad! No matter what I did, pumping the new Novo resulted in a brief drop in the first hour (like from 180 to 130) and then the CGM breadcrumbs started climbing again. I reasoned my way into first trying a new infusion set @ 3 a.m. after several correction boluses. When I woke up @ 6:30, the CGM showed the same dip to 130 @ 4, then the inexorable rise to 220. Note that my correction bolus @ 3 was a full 50% higher and I set a TBR that was also 50% higher. Wow! At this point I was starting to wonder just how much Novo I was going to need compared to Huma. Then, I asked what I would do if I had the same results back on Huma … I would …

Change to a new vial!




Back to something approaching normality.

I love diabetes!


@Yoga0, I am in the same boat as you. I also have crappy Caremark who dropped Humalog for Novolog. I switched to Novolog and my I/C ratio is terrible.
Humalog…1u for 19–26 Carbs
Novolog…1u fir every 2-4 Carbs

Even tho I eat about 100 carbs daily, I hate taking so much insulin ( also causing weight gain)

I saw my Endo today and he agreed to supply me with 3 sample bottles at every visit! I am so glad to be going back on Humalog!!

Generally Novolog and Humalog should have actions that are much more alike than different. Yours are dramatically different (like 10 times different) suggesting something going on. You should check with your endo, but you may have developed an insulin allergy to Novolog. Insulin allergies may manifest as a rash at the injection site, but they may also occur as an immune reaction where your body generates antibodies to the insulin and essentially renders it ineffective. When this happens you can have severe insulin resistance. Your doctor (or specialist) can check for the IgG and IgE antibodies to help confirm such a diagnosis. This would be a valid basis for a letter of medical necessity. Should you have such an allergy there are also other things that can be done to suppress the immune reaction.

I’m curious how often this really happens. my endo has told me that basically novolog and humalog are the same. I’ve never tried Novo.

We are told they are rare, but in my mind rare is like 0.01% chance of occurring. This source says that as many as 2.6% of people on human insulin develop and allergy. Which means that 1 in 40 may experience an allergic reaction. Note that these reactions vary from mild rashes to extreme insulin resistance to potentially fatal reactions.

it just seems to me we have a high percentage of folks here who have problems w one or the other. like @David_dns says humalog is like “injecting water” (pardon me if I got the wrong insulin) and @Doris_D reports the same with one of the short actings. maybe it’s just that those who have little issue w substituting one for the other aren’t reporting here, and those who DO have a problem are over-represented

Well, almost. Humalog does nothing for me, as you say–zip, zero, nada. Doris has a strong, almost allergic reaction to it. As does Thas, if memory isn’t playing me false. But in the general case, they are supposed to be functionally identical for all intents and purposes. I’ve heard that from many people, Bernstein included.

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@Brian, thank you. I will talk with my Endo, however, this poor results started as soon as I switched to Novolog. I have given it a 6 month trial. Luckily, I have kept my A1C at 6.8. It s a relief to go back to Humalog.

We have caremark too but they switched us to novolog last year. If your control is worse or issues like a rash, can you appeal to caremark to cover Humalog?

I notice only small differences between Humalog and Novolog and probably if it were a blind trial, I would not be able to tell the difference. I have sampled Apidra a few times and am not sure if it is hugely faster in and faster out for me. I have never had insurance coverage for Apidra, so have never worked hard to prove that it might be better for me.

I always joke that we need an insulin exchange program so that those forced to switch to Novolog could trade with those who have been forced to switch to Humalog.


Yes, I could but it would be too expensive.

@Gail12 - that’s a huge difference! With that much of an increase, your TDD must be very large, did you have to make a similar change to your basal rate (maybe your not on a pump?).

With the sample vials in hand, I would definitely look into appealing to CareMark. This way you will have something documented should you decide to push for Humalog in the future. Also, with that big of a bolus difference, the price differential isn’t as extreme?

@Yoga0, that is the odd thing, I have not had to increase my basal , which is Levemire also made by Novo. I have sent a request to my Endo to have my IGG And IGE antibody levels. ON Novolog I must pay 25% of the cost, for Hmalog I would have to pay 50 % of the cost. It s just too much for me. I am hoping to hear back from my Endo by Monday.

IgE antibodies are the ones that result in immediate allergic reactions (rashes, swelling, etc.). IgG antibodies are the ones that can make insulin ineffective. Good luck, I hope you get this figured out.

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Thanks Jen. I do not have any swelling or rashes. Just an update, I started back on Humalog this morning and sure enough my Carb Ratio is still 1u-19 carbs :blush:

My Endo says my insurance won’t pay for the IGG . Now that I have been back on Humalog fir 9 days my IC Ratio is as bad as when I was on Novolog. Any suggestions?

Well, the only other fast-acting one out there is Apidra. Is there any possibility of trying that? (I use Apidra for corrections or high-carb meals because for me, it is noticeably faster acting. Your results might vary, of course.)

Have you done:

Basal rate testing?
Rotated your injection sites to new/rarely used locations?
Tried a longer needle, injected at an angle to get to the sub-q level?
Tried an intramuscular (IM) shot at varying I:C levels?

I will check to see if Apidra is covered/or can be covered by my insurance. Thanks.

Another factor might be that I started Tresiba on 4/26,. Maybe I just need to give it a little more time. I have been a T1 for 54 years, yet somethings are still a challenge😊