FIASP for Insulin Pumps


I see a drop in roughly 20 minutes


Just to chime in with my own experience:
I’ve used Fiasp in an Animas Vibe-pump and for the time being in an OmniPod-pump, and I´ve had two different results.

Fiasp in the Animas Vibe didn´t work well. I got site irritation (using only my stomach), severe stinging even when dosing only 1-2 units and the cannula left a lump that didn´t go away for about two weeks. I used more insulin than I did with Humalog, but had less and fewer spikes.

I just started using Fiasp in my OmniPod and so far it works great. No site irritation (using my arms this time), no stinging and no lumps. It seems that I might need less insulin and maybe actually can bolus just five minutes before eating carbs. Yesterday morning I ate oatmeal porridge. With Humalog I would have to pre-bolus 45-90 minutes ahead (using a CGM and “waiting for the bend”), but with Fiasp I waited five minutes without wating for any bend, started eating at 5 mmol/L (90 mg/dl), started spiking after 45 minutes and ended after 1 hour at 7,8 mmol/L (140 mg/dl), dropped 10-15 minutes later to 6 mmol/L (108 mg/dl). Even stopping my pump for 1 hour at this point didn´t stop my from slowly drifting to close to 4 mmol/L (75 mg/dl), so I guess I have to adjust my ratios. My basal seems to work fine most of the time.

The no-stinging and no-lump-part with the OmniPod could be due to how fast the pump administer boluses. I had my Animas Vibe set to the highest rate possible while the OniPod administer boluses really slowly. I didn´t know that slow might be better than fast before I was told so when I switched pumps, and for me I think this might be the biggest difference. And off course using new sites with unharmed tissue.


Thank you for a detailed response on how you responded.
Did you still use your previous carb ratios, etc?


It could be, but I used Fiasp in a Medtronic pump which is super slow at bolusing and had issues. I think my issues were more about the nature of the insulin than my sites though, so you could be on to something.


I do for now because I´m only seven days into my second experiment with Fiasp. I think I have to adjust my I:C-ratio, but my basal seems to be OK. Right now 1 unit covers 10 gram carbs, but Fiasp seems to cover much more. My guess is 1 unit pr 15 grams or even more.

One really strange thing is that Fiasp in my OmniPod irritates even less than Humalog did. I can´t even see where the cannula has been when removing the pod. This puzzles me a bit considering the bad experience I had when I used Fiasp in my Animas Vibe.


I’m in the group(s) looking for more rapid onset and shorter tail. I have to pre-bolus 40-45 minutes before meals to keep post prandial levels down and I bolus to keep post prandial levels peaks reasonable. That tends to push me low in the afternoon and evening. So I snack to either prevent or treat lows. I’m also pretty aggressive and maybe a bit early in treating highs. I’ve learned that BG lower than CGM means glucose is on its way down. Still over treat highs from time to time.

I currently use Novolog and change infusion sets every 3 to 3 1/2 days, but have gone 4 days upon occasion. So I don’t expect any skin or site problems with FIASP. Also, my carb ratio isn’t constant over a very wide range. I’m trying to get a handle on level of carbs/type of food that need a larger bolus.


Well. My endo said he felt all rapid acting was about the same in his experience, and I don’t think he has had any experience with fiasp yet, and didn’t seem to have any samples. He gave me a sample of Apidra which seemed to be all he had at the time, which is one I really wanted to try, but unfortunately it didn’t end well. As seemed to be a somewhat common problem in pumps, I ran into crystallization issues. The crystals would end up getting stuck in the infusion set end (if I unclipped it it would flow fine). I had problems after one day, and when i went to replace my site after it got occluded, the new one got clogged when priming it. It is unfortunate as it did seem to work faster for me.


Wow. I’ve heard about those problems, but have never had them myself – I use Apidra in my pump all the time! Sure, I get the occasional occlusion, but they’re rare and usually toward the end of a 3-day site. I’ve gotten in the habit (most of the time) of changing sets every 2.5 days and have minimal-to-no occlusion issues.

I wonder what I’m doing differently that makes it behave differently? Dunno if it’s my TDD? Or the fact that I have my Animas Vibe set on fast delivery? Or the particular sets? Don’t think it’s the “pleasant” Chicago area climate that’s involved…


different materials used in the tubing used by displayname and Thas, perhaps? Many years ago MM bragged that they had improved tubing so that it wouldn’t cause occlusions (crystallization) unlike the early infusion tubing. Also, Velosulin was developed with pumping in mind. The idea was that it was buffered to prevent/reduce crystallization issues for pumpers. I used it for roughly 6 months, until Humalog hit the market.

One might find it surprising that all of my many “no deliveries” were when I used Quicksets. I nearly quit pumping but just as I was about to put my pump in the closet, I found out about Sure-T’s. problem solved. With Sure-T’s, I think I’ve had maybe 3 “no deliveries” in over a decade. I’ve been on them so long, I forgot what year I started using them.


For my case I am using Tandem stuff, and using the Tandem equivalent of Sure Ts (Contact Detach, or TruSteel if you are using the new version).


I could be wrong, but I think there is one mfgr for both the Sure-T and Contact Detach. It should be Unomedical.


That is correct, they are made by Unomedical like all other sets are apparently :). So much for options :woman_shrugging:


We are going to switch my son from Humalog to Fiasp in the coming days. He also uses OmniPod. Did you have to make any changes to your basal programs or I/C ratios? We had duration set to 2-1/2 or 3 hours. I assume we need to reduce that to about 1-1/2 hours? Any advice you have for pump settings would be helpful.


@jane10 - here is a quick summary.

I/C ratios, correction ratio, and basal rates pretty much stayed the same for me.

Basal schedule - for basal testing, I make rate change with Fiasp 1 hr before I want to see the change. With Humalog it was 1.5 to 2 hours. When changing to Fiasp I moved all my basal times about 0.5 hours forward.

DIA - I shortened the DIA by about 0.5 hours. I use a DIA of 3.5 hours for Fiasp in the Omnipod. I used to use about 4 or 4.5 for Humalog. Omnipod uses a linear IOB decay so if you are using a different pump you may find you need a longer number. There is still Fiasp around after 3.5 hours but it does not do a huge amount unless you give a big bolus.

I actually use AndriodAPS for IOB calculations (not omnipod) and it has a better insulin action curve. I use a DIA of 5.0 hours with AndroidAPS. You can see below that after 180 minutes (3hours) there really is not much left, but if you give a huge bolus that little bit could still impact your Blood glucose.


I am new to this forum and found it by searching for Fiasp and Pump. I was recently supplied a couple of sample Fiasp vials by my Endocrinologist and I am using it with my Tandem t:slim X2 pump and having excellent results. I realize that everybody with Diabetes is different but I thought I would provide my specific results.

I have only been on the Tandem pump about 2 months now and was previously using the Animas Vibe pump. First, a comment on these two pumps… I find that the t:slim X2 works much better for me because the bolus insulin is dosed at a much slower rate than the Animas pump. For me, this has been a real plus for the site working better for longer periods than I could get by with on the Animas Vibe. In both cases, I also use the Dexcom CGM which was integrated with these pumps… Dexcom G4 with the Animas Vibe and Dexcom G5 with the Tandem t:slim X2. The CGM has been a HUGE game changer for me.

Now to the Fiasp results with the Tandem t:slim X2 pump. To sum it up, for me, it has been truly amazing. Like others, I was having to bolus Humalog 30 minutes or so before a meal in order to avoid extreme food spikes. With Humalog, if I bolused at the same time I ate, it was not unusual for my BG to spike at 250 or so and not come back down below 200 for about an hour. I have only been on my trial with Fiasp for about a week and a half but my food “spikes” are basically nonexistent. I even did an experiment with a high carb mexican lunch at around 110 carbs and, with the Fiasp bolused at the same time my meal was delivered, it peaked at 132 (I was at about 80 when I did my bolus). With Humalog being bolused with the meal, I would have probably spiked in the high 200s or low 300s and would have taken me 2 to 3 hours to get back down to anywhere near 100.

I have noticed what others have mentioned about the site getting less effective as you approach the site change. With Humalog, I was routinely getting 4 days out of my Tandem pump and 3 days out of my previous Animas pump. Using Fiasp, I can barely get 3 days. In one case, I needed to change the site after about 2 days as it became less effective on larger boluses.

As for the settings, I started out using basically the same pump settings I had used with the Humalog and, for the most part, I have continued with those. I do have a more aggressive carb ratio than many as mine is 6:1 so I don’t know if that has a positive or negative impact on how effective Humalog or Fiasp are for me. One thing I have noticed is that it appears that the Fiasp works its way out of my system quicker. I had to reduce my IOB duration by about 25% from what I was using with the Humalog.

As for the site pain or irritation, I haven’t had any of that, even with large boluses. I just have to change it a little quicker than I did with Humalog.

In my case, the negative is the potential for shorter site effectiveness but the positive of the much better meal control greatly outweighs that negative. The other negative is that Fiasp isn’t approved by my health insurance at this point and the cheapest I have been able to find it in the US is $282 per vial. My insurance company updates the formulary every 6 monts so hopefully it will be added in July.

I will also add that my A1C typically ranges from 5.6 to 6.1 so I’m pretty well controlled. My last A1C was 5.4 and that was the lowest I have ever had since my Type 1 Adult Onset diagnosis about 20 years ago. That was also using Humalog but I have been managing the meal spikes by bolusing 30 minutes before the meal which has definite risk and has caused Hypo issues a few times when the meals were delayed (especially in restaurants).

Hope this helps. After I have some additional time with the Fiasp, I’ll provide another report.


I have tried “R” and novorapid in the pump so far for basal only, corrections and bolus for meals were via pen. . Novo seems better as basal than R. Will also try apidra. This is not recommended for very low flowrates as apidra can crystallize and block tube. In my case basal needs are very very high about 3 u/hour so this should not be a problem.

What do you see as an advantage of FIASP ?


The main Fiasp advantage I’m seeing is the fact that it goes to work much quicker than Novolog or Humalog (the only other two insulins I have experience with). Most recently, I was having to bolus Humalog around 30 minutes before eating in order to coordinate the action of the insulin to coordinate with the action of the food. With Fiasp, I bolus at the time I start eating and it goes to work extremely fast. In my case, I would say in less than 5 minutes. According to the manufacturer claims, it starts working in 2 1/2 minutes. With Fiasp, I’m not having any huge spikes at mealtime like I was having with Humalog… Especially if I bolused Humalog at the same time I started eating.


I have a single Fiasp pen as a trial - but that’s one of the most important advantages that are making me interested in it.


Well, I just got some sample vials of fiasp, so I will see how it goes for me.
I can usually get 3 to 4 days without issue on a site with novolog. So if I lose a day per site I wouldn’t be too concerned as long as it actually works!
I will report back in a week or so with my report.
I use the Tandem X2 pump and dexcom G5. But run Xdrip+ on my phone to monitor the G5.


I have just one sample - not enough for a trial… waiting on getting some more. Looking to see your results, @Hammer!

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