Bad insulin? Or resistant to specific type of insulin?

I’ve been needing more and more fast acting (but not basal) insulin lately. I chalked it up to getting less exercise and let it go until yesterday. I had a standard frozen meal for lunch that should have needed 7 units of Novolog in the beforetimes. I think I took 10 initially, which normally would be enough nowadays. It did nothing. My blood sugar got to 360 before it even started to come down and by the time I was down into a normal range I had needed 37 units to do what 7 normally would. Then pretty much the same thing at dinner (just less carbs so not as bad). I’m getting near the end of my 3-month (probably more like 6 by now) batch of Novolog cartridges and I had just started the second to last cartridge the day I needed that absurd lunch bolus(es), so I thought I’d steal some of my son’s fresh Humolog to see if it was me or the insulin. He doesn’t like using a syringe to draw out the remaining insulin, so that’s on me anyways and he had a few pen leftovers for me. His insulin brought my blood sugar down so fast I got whiplash. Even with a beforetimes dose. My Novolog has an expiration date of 12/21 and has been stored in the fridge since it arrived, so it shouldn’t be bad. Could it still be bad? Could my body just not like Novolog anymore and work better with Humalog? I need to switch up my allergy meds every now and then for this reason, but I didn’t think insulin was the same way. I’m wondering if I should toss my last vial and order fresh Novolog and hope that fixes it or try switching up insulins.

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Has you noticed this increase in insulin only in this one Novolog vial or has it been occurring? 7 to 37 units is quite the increase for not being ill, stress, lack of exercise or other typical causes of insulin resistance.

I would try a new vial of Novolog first. Also try injecting into a different site.

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I think the other cartridges (or just me) have been needing a few more units (i.e. 9 or 10 instead of 7) for a while now, but this new one is something else entirely. I’ve actually started exercising again, so that excuse was less valid. No other illness, new stress, or other issues and I pretty much inject into a different site every time, but trying the last cartridge is a good idea. Maybe it’s just the penultimate cartridge that is really bad for some reason.

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Hi @bwschulz,
I rarely think bad insulin is to blame. To make sure I understand this correctly - is it a pen, or a vial and syringes you are using?

If it is a pen, I think it is much more likely that the mechanics of the pen are not delivering properly.

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It’s a pen with replaceable cartridges (see image below of a similar one). I’ve had it for about 15 years now and never had a problem besides the rare jammed needle (pull needle out after shot and insulin you thought you just injected sprays all over you) and one time the glass cartridge broke inside it while injecting for some reason. I’m 99.9% certain the insulin is going in properly with this cartridge, and I can see the level/volume has dropped as it should have.
If it’s rarely bad insulin could it be that Novolog doesn’t work well for me anymore and I should switch to something else?
image

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Well, this might not be the cause of the issue you are seeing. But… any mechanical device has components that can get worn down over time. Especially the plastic components, like the gears inside.

And it is really hard to visually see a small change. Like if the units are now 10% smaller than they once were, it wouldn’t really be something you could see.

After 15 years, that pen may not be delivering the exact same amount that it once did.

Again, maybe not the cause of what you are describing, but after 15 years it might be good to treat yourself to a new pen!

I think other factors might be more likely. Changes in metabolism, changes in diet, changes in activity levels, changes in amount of sleep, stress, hormones, etc.

None of us are completely static. Our bodies are constantly changing.

If you really want to drill down into the issue, you should try the same insulin with a syringe, and see if that changes anything. And then try a different insulin, but also with a syringe.

Just change one thing at a time:

  • First - use a syringe instead of the pen, but with the same insulin.
  • And then after that test, next try a different insulin, but also with a syringe.

I think that lets you figure it out.

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This seems like something that should be possible to test. How about deliver 5u into a small saucer, and then suck it up with an insulin syringe and see if it’s 5u in there? That wouldn’t be sensitive enough to show small dosing errors, but it should reveal if there’s a big problem with the pen.

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The main problem wasn’t a small difference, it was needing 37 units instead of 7 and the first 20 or so not doing anything. But I have a new suspicion. I’ve used this thing so long I should be able to switch cartridges while asleep, but if I didn’t fully seat the pen piston on the new cartridge plunger the first 20 or so units would have just been taking out the backlash before the piston started pressing on the plunger and dispensing units. It’s unlikely and has never happened before, but that’s the only thing I can think of since the problem didn’t replicate with a syringe or when I put it back in the pen. It’s still really weaksauce insulin, but more like 2 for 1 bad not 37 for 7 bad. But I have a new plan to demonstrate the differences between the two Novolog vials and Humalog. Tomorrow for lunch I’m going to make a big pot of jambalaya with known carbs, split it exactly three ways, and have the same thing for lunch three days in a row. I’ll use the same dose of insulin (delivered with a syringe to take the pen out of the equation) exactly when I start eating it each day. Then I’ll screencap my Xdrip+ profiles 3 hours later and post them here. It should be useful for my doc and entertaining to post here.

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I used Humalog for the first 13 years of my T1D or so. But then it started doing what you’re describing above. I switched to Novolog for one month and it worked so well that it scared the crap out of me. I switched back to Humalog for another month. It was a sluggish disaster. And then I switched back to Novolog. I still use Novolog now. It’s not as efficient for me as when I first switched to Novolog, but it’s still performing better for me that what was happening with Humalog.

Back when I was working with the CDEs at Gary Scheiner’s group, they told me that some diabetics develop an allergy to insulin after being on it for so long…so what they have to do is switch back and forth between two kinds on a monthly basis so that the body stays receptive.

Just wanted to share that data point with you. I hope it is a mechanical delivery issue that is easily fixed. But the efficacy of Humalog in your system when you corrected with it makes me suspect something more in line with what I experienced. Just my two cents, though. You know best about what you’re seeing!

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Thanks- that’s great feedback. I’ll get some plots showing exactly what is happening and let my doc know. Hopefully I can get this figured out before I run out of Novolog and need to order more. But if that happens I can always just steal a Humalog pen from my son.

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If you need some Novolog pens in the meantime, just let me know.

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I wondered whether this was a possibility, too. I’m interested in doing this, but if you don’t mind me asking, how did you manage having two prescriptions for fast acting insulin? Do they allow you to fill two prescriptions? I have a Dr appt w/ my endo later this month and would like to request this!

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I had a sample from my endo and then a friend floated me some. I’ve not ever successfully had rxs for two different fast actings at once but it might be possible with a good endo and pharmacy.

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@T1Allison Ah, that makes sense. I will see what my endo says end of month about having 2 short acting insulin prescriptions. She may not know and then I will try Cigna.

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May I ask which insulins you are thinking about going back and forth with? Just wondering if I can help somehow. No pressure to share that info if you’re more private.

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I’m on Humalog now (with DIY Loop and OmniPod), but I’d like to try Novolog. I tried it last fall after my Dr wrote a prescription for it, but I’d like to try it for a longer period, or perhaps maybe alternate the insulins as Gary Scheiner said sometimes helps. I received 3 vials of it but then my prescription reverted back to Humalog. I’m going to ask my endo if there is a way to split the prescription between the two. I’ll let you know what she says!

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Experiment completed & plot below.
For three days in a row I had the exact same meal at exactly 11:30AM with the same dose of insulin (8 units) using a syringe for the Novolog cartridges to eliminate my old pen as a variable. My son wouldn’t let me use the syringe on his pen so that one was dosed with the pen.
I was fasting at the time with no insulin onboard, but my blood sugars were a bit different on each day (84, 98, & 127 respectively), so I zeroed them out to the first day. I was also sitting on my ass working at the computer for the whole time each day, so no differences in physical activity.
The Humalog wasn’t as strong as I’d hoped/feared (I thought I’d low out with that dose), so that was a bit of a surprise. I guess the strong reaction the last time I took it must have been more due to the meal. But the Humalog did keep working for longer than the 2nd Novolog cartridge. Again, note that I offset the initial value (127 for the Humalog) so it didn’t actually take me down to 50.
The bad Novolog was indeed bad, and I took 5 more units at 3PM to get my blood sugar down by dinner. I actually received a call from Novo-Nordisk yesterday, since I’d asked a question about this on their customer support site. They offered to replace the cartridge, but the process was more trouble than it was worth. However, the customer service rep did say that they occasionally get reports of ineffective vials or cartridges and replace them. I hope this is useful to someone- it was useful to me. I’m emailing it to my doc now to help figure out which insulin to switch to.
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Wow, very good analysis, and vey helpful for future issues I may, or should I say, will experience! I’m really glad you figured out the root cause of the huge increase in insulin requirements, too.

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Awesome experiment @bwschulz! Great work!

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Nice work, and I am officially jealous you got to eat Jambalaya three days in a row!

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