Experience using Fiasp?

So how is it working for you through a pump?

We only use it for corrections with syringes, our endo suggested it that way for specific occasions. So far so good!

@Patricia5 - Have used FiASP in an Animas Vibe pump for 4 months. No different than Humalog as far as the pump function goes.

Significantly faster onset (15 Min) and shorter tail (3-3.5 hour duration) than humalog. I like it.


Same for me, except I’m using a Tandem X2 and had to dilute the Fiasp about 20% to avoid an unexplained loss of effectiveness when the cartridge level dropped below approx. 50u.

There are several similar topics here that have posts that might help you out. I think you’ll find the experience runs the gambit from ‘no problem at all’ to ‘I just can’t make this work’.

1 Like

I use it with my Tandem X2 without issue.

1 Like

It’s been working well for me for over six months in my Medtronic 670 G. I did reduce my insulin on board by 15 minutes to 3:15.

1 Like

I would like to try it in my Tadem pump (TSlim2) but, Dr. will not prescribe saying Tandem will not verify it can be used in their pumps. I called and they told me the same thing but, would not say why. I can only assume it is not the tubing but, their algorithm given different onset and tail than other fast acting analogs. Hoping with the software upgrade to closed loop by end of 2019, they will have fixed this issue. Anyone know anything more on the topic?

Medtronic will not recommend Fiasp either as they have not tested it in their pumps; however, my Endo was willing to prescribe it.

They haven’t gone through the process of getting Fiasp approved for pump use yet. I’m not sure if that would be Novo’s responsibility or the individual pump companies.


I havre recently switched to the Tandem Tslim pump (from an Animas Ping) and have experienced problems using Fiasp with the Tandem and I may need to consider dilution. Did you dilute with Novolog or some other matter.

I also feel like the Tandem does not register the full amount of insulin that I put into the cartridge.

I appreciate your insight or anybody else’s for that matter. Am seeing my diabetic educator soon.

Initially I diluted with Humalog as I have a lot of it. Then I got Humalog diluent (FOC) from Lilly and used that to make dilutions. Both worked equally well, but I wanted to have one kind of insulin being delivered for consistency’s sake. In reality I didn’t see a difference. I think Novolog or Novolog diluent (Novo has this as well) is a better choice because the excipients in the two insulins are probably identical.

My CDE and Endo supported me doing this (my idea, not theirs) but I’ve been with them a long time and they trust my judgement. I don’t know your relationship with your CDE/Endo, but I can imagine getting push back. Up to you if you want to try it anyway.

Thanks for the information. Yes, I am lucky to have a good Endo who supports solutions that work. His colleague uses FIASP but has not had the same problems as I do. FIASP was just recently approved by my insurance company (last summer) so its been trial and error but I hate the idea of going back to regular novolog or humalog. So slow and I was always in a fog.

1 Like

Like @Don1942, my endo was fine letting me try it out, even though it’s “off label” for pumping. That just means the pump makers can’t officially ok it. I’ve heard it said that it’s a bit more viscous than Humalog or Novolog and that can cause delivery problems in some pumps. But I haven’t had any problems with it mechanically in my old-school Paradigm, and I definitely prefer it performance-wise. I was having to pre-bolus anything up to an hour before meals with standard insulins, but Fiasp much more reliably kicks in within 15-25 minutes.

I’ve had some issues with the shorter tail. With high-fat meals you can find your insulin fading as the delayed carbs come on. I’ve gotten much better at setting dual boluses for that reason, and sometimes I may add a little more insulin if I see my CGM ticking up after a couple of hours. It can also do something more problematic, though. On one occasion the fat delay effect was pronounced enough that the insulin came on too strong too early and I had a pretty bad hypo, one of those eyesight-fades-out ones. Ah pizza, how you do hate on us T1s.

Since starting with Fiasp about eight months ago, I have had two or maybe three insulin flow blocked messages. Nothing happened after the messages.

Until recently I was using Fiasp, but I went back to humalog because I had a lot of it. Fiasp worked very fast originally, but seemed to lose effectiveness after several months of use. That is another reason I went back to Humalog, so I could take a little break from Fiasp and see if it helps to be more sensitive. I think it was still working faster than Humalog, but just not as fast as it did originally. I have wondered if it is causing more scar tissue buildup and that is the cause of the lessening effectiveness.

I have had some noticeable issues with it. I had 2 occlusions when I used sets for 3 days (I usually have to change them within 2), and the occlusions were somewhere in the tube or cartridge as no insulin would come out with it unhooked. I had several instances where immediately or sometime within the first day a new site would be leaking out profusely. Definitely seemed worse in certain areas, though strangely enough the areas were rarely used ones that I was trying to utilize because of the scar tissue/lipo-whatever build up of the areas I used forever. Surprisingly those areas, even though they had poor absorption, never leaked.

Over all I would still use it, though it is not as amazing as I would have hoped. I started seeing a new endo and one of the first things she said was “you know that this is not approved for pumps right?” and I said “well it is approved for pumps in Europe, and I had my regular doctor prescribe it off label” and she said “OK that’s fine, it seems to be working fine”.

The FDA has not approved Fiasp for use in any pumps (nor approved for Pediatric usage at all). Our Ped Endo has prescribed Fiasp for us for Pediatric use in a pump (Tandem t:slim X2 w/ Basal-IQ) as an off-label prescription. Our Ped Endo is anticipating the FDA will be approving this for both Peds and Pumps (timeframe unknown until it happens) so our Ped Endo was excited to gain experience with one of her patients (us) in advance of the FDA approval.

We find the Fiasp works awesome in conjunction with the Tandem Basal-IQ algorithm.

We use Fiasp straight from the vial with no mix or dilute with anything else.

We have had no occlusions problems while running Fiasp through our pump.

EDIT: The FDA submission for Fiasp for Pediatrics was announced on March 1, 2019. The FDA will act on this when the FDA acts on this. Novo Nordisk stated they expect a response from the FDA in early 2020.

EDIT2: I can not find where/if the Fiasp was also submitted to the FDA for use in a pump. Also no idea if that approval would have to be for each insulin/pump combination or if one approval would cover all pumps or if it would be by pump manufacturer or what.

For us, the off-label approach has certainly worked well. However this clearly requires a Doctor who is on board and excited to also try this out.

How many slices?

We have found one slice of pizza easy.

Two slices hard.

3 or 4 slices and AAAGGGHHHHH !!! ■■■■ ■■■■ ■■■■ ■■■■

Pizza is never easy to bolus for.
I have no problems with only a few slices, but I do not have self control. I know I will pay, and I self endulge when I get pizza (not very often, it is one of my special treats!)
But, I have learned with larger meals, hit it harder up front!
Also, so a small initial bolus, then shortly after follow up with the larger bolus. This seems to keep the initial drop from being too severe.
I know if I start eating with a solid and level BG in the 80s, then a small bolus followed with a larger one works best.
If I have higher BGs to start, I hit it with as large of a bolus as I feel safe with.

Oh, I think this was 4 slices. Hardly seems worth breaking the pizza barrier if I’m not going to go all the way to pizza mach 4. Which was why I’d bolused pretty heavily for it, and probably leaned too heavily on the front end of the dual wave. I know it’s gonna spike me pretty hard, so I guess I was trying to get ahead of it, and next thing I knew I was standing at the playground with my grandkids and my eyesight went. Fortunately my daughter was there and had a candy bar.


That pretty much exactly describes my approach, yup.