Insulin not working - Fiasp?

I’ve been trialing whether Fiasp is any good for me. I’m on my third vial now and I’m using it on the pump. I don’t know whether it’s Fiasp not working, but there are some days where my sugar is crazy high and I’m injecting like 10 units with the anticipation of eating soon, only to find my sugar not drop after the 20 min mark… and sometimes even start climbing upwards. I didn’t have breakfast this morning, though i bolused for one… and my sugar is still hovering in the 150-160 mg mark despite me giving correction boluses throughout the morning. I ended up skipping breakfast altogether since I couldn’t get my sugar under 100.

Then came lunch, same thing happened. I bolused around 1 hour ago and I’m still in the 150-160 range withe the BG drifting up. Also to add, I’ve got my temp basal set to 150% - my sugar should be coming down by now. URGH!!! What is going on???

I’ve just given myself another 6 units manual injection of novorapid and hoping it will come down after 20 mins… it may stack with the other 6 units of fiasp I already have on board but at this point I don’t think its actually doing anything. Something is not right, I’ve been high all morning and nothing seems to be working.

**Update - My manual injection of novolog has started working after 20 mins and my sugar is on the way down. Given this is the second time this has happened in 7 days, I’m scared to use Fiasp any further in the pump. I’m not sure whether a manual injection of Fiasp would have brought my sugar down, it didn’t the last time it happened but I only bolused a small amount that time (like 1-2units).

This is pretty common with Fiasp. It works fine for a while and then doesn’t seem to work at all for some people. I would switch back to Novolog.

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Has anyone been able to find out why? How strange is that? I thought fiasp was made with the same recipe as novolog except with the addition on vitamin b12?(may have remembered that incorrectly). I did read somewhere that this happens but after long time use, but I’ve only used it for a couple of weeks. Does this only happen with pumps?

Yes I probably need to switch back. What a waste of insulin.:disappointed:. It’s quite scary when you try to bolus and bolus and your BG just kept going up and you have a bunch of insulin on board that you don’t know is going to work or not.

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The same thing happened to me with FIASP. It is very disappointing.


I’ve had this happen with Novolog. The insulin is either really spoiled, for whatever reason, or, for the same, whatever reason, insulin resistance has taken hold or … there’s a combination of both going on.

There are so many variables to consider, it’s mind-blowing. :frowning:

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I have had similar experiences with both NovoLog and Fiasp.
I have been on Fiasp for two years. For the last year, elevated BGs have been less frequent.

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@Marilyn6 if I remember correctly, you are on MDI right.? So this issue isn’t to do with pump use with fiasp ?

@Don1942 @Tapestry i haven’t heard this before, is this a common known issue with novolog? Sometimes it could be just bad insulin in the batch but once you change it out it starts working again. But for me fiasp is a bit different, the first time it happened, I changed out the site and the cartridge of insulin using a new vial. It could have been the site has stopped working, i couldn’t rule it out. But the episode yesterday, I had changed the site only and it wouldn’t work until I changed the cartridge with novolog insulin so I was sure it wasn’t site related.

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Yes, I am on MDI.

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Twice I sent the questionable vials of Novolog back to Novartis for testing and was advised there was no issue. I believe, in my case, the unexplained highs were a result of something I ate negatively effecting my insulin resistance or possibly a pump malfunction.Just a guess.

It’s hard to pinpoint exactly what it is because there are so many variables at play isn’t it? But it is quite scary when the bg won’t go down with the excessive amount of insulin in the body.

That I don’t know.

What is common knowledge though are … variables. There are so many, it becomes a dart game sometimes trying to figure it all out. No sooner do we figure it out, yep, rinse and repeat.

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This happened to me, too. I was doing a trial of it, too. It seemed to work (though never FAST as it was supposed to be) initially for the first one or two months, but then suddenly stopped working. Like I was injection saline. I tried different vials, different injection sites, etc., but nothing resolved it. I switched back to Humalog which immediately worked properly.


This happens to me too. I’ve always figure it’s a bad site not absorbing. I don’t know what happens to the insulin that is not absorbing however it goes into my body.
Anyway most of the time it is corrected with a new site.