Fiasp-good and bad

Hi! I’m new to the community and have had Type 1 for 47 years. 2 kidney transplants, etc. I came on because I wanted to know if others have the same apparent issues I am having with Fiasp use in my pump-boy does it hurt going in with any bonuses and already I have an infected site. It worked so much faster than my Novolog, but I dont think I can handle these side effects. Anyone else get over these initial issues? Or even have them?

I find that location affects the sting, and canula length also affect it (another form of location really.)

Funny thing, the closer to muscle stings LESS. At least for me anyways.

I experienced a bit of a sting when I did a really large bolus to cover a restaurant meal, but as a rule, nope, haven’t felt a thing. The one thing I’ve noticed is that it fades pretty markedly on the 3rd day of an infusion site and I’m having to be more aggressive about changing them out than I was before. That might indicate that I’m getting more inflammation at the site than I was. Or maybe Novolog was doing the same thing but the difference is more obvious with Fiasp because it generally works so much better for me. In any case, I’ve been on it for about 3 weeks now and it has been working really well for me.


I had edema on one foot and was also painful to walk on when I used novolog. I did not connect it to novolog untill I switched to Apidra when it became available. Apidra was a new kid on the block at that time. Then, I noticed my foot pain and swelling went away. I then connected the coincidence to bad side effect of novolog to my body. Keep in mind YDMV. Just to see if this theory was true, I tried to switch back to novolog again, and the swelling, pain in my foot came back. CONCLUSION, novolog is bad for me. So Apidra became my insulin of choice.

Then came Fiasp. I switched to Fiasp and the foot pain and swelling came back. Fiasp is same as novolog plus some other additives. So unfortunately I cannot use it. In the beginning it was faster than Apidra. Then slowly become same as Apidra. I used it for 3 months, then the pain was too much, so I switched back to Apidra.


There have been many reports of people pumping Fiasp and have experienced infusion site irritation, red color and inflammation. This swelling and red color tissue at the infusion site can progress to an actual infection. I had this problem when pumping Novolog, a very similar formulation. If I ever try Fiasp, it will only be as an occasional syringe or pen correction due to my allergic reaction to Novolog.

Oh wow! I have had one legged swelling for a good year now. No one can figure out why. I wish I werent so allergic to everything! I also noticed that I had a concurrent gut reaction when I was on the Fiasp which I didn’t have on the Novolog. But the Novolog is so slow for me. Oh well. I do love the pump, so I guess we have to make choices. Just hope I dont become allergic to ALL insulin’s…

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Interesting-Yeah, I know if the bonus is over about ½ of a unit, I feel it. Maybe I should try the shorter length tubing. But the current red lump in my abdominal area from the Fiasp site is still REALLY painful, so I think I’ll wait a bit longer before trying the Fiasp again.
Glad to know how people are adjusting things to make it work.

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Yeah, I think youre being smart. How about Humulog? Is it different/better for you? And do you use the Apidra in a pump?

Where are your sites being placed where the muscle is close? Quads, abdominals?? I’m pretty underweight and mostly use my abdominal area, but I do have a layer of fat in this area anyway somehow…

So you didn’t really get the red painful bumps at all? Are you on pretty minimal insulin so you dont need large bonuses? Or are you using a feature of the pump that extends the bonus?

Actually, up on my ribcage worked fairly well. I was leary, but tried it anyway.

Nope, no painful bumps. My TDD ranges between ~55-70 units. I’m currently using my old MT Paradigm 723, and yes, it is designed to do very slow, gradual delivery, so maybe that’s why. In this pump that rate is hardwired; in the newer ones you can select fast or slow. I had my 670G dialed up to fast. If I go back to try auto mode again with Fiasp, something I’ve been considering, I may have to experiment.

I haven’t used Humalog in many years. I did use if when it first came out in 1996. It was the first rapid acting analog insulin available. I would expect it to work for me now but I’m sure I’d have to make some adjustments. Then I tried Novolog for several years and had to quit it when I started experiencing the red inflamed “pump bumps.”

Yes I use Apidra in my pump. I’ve been using it successfully in pumps for about 14 years now. There are warnings about it not being compatible with the plastic in pump cartridges as well as the infusion tubing. I’ve never had a single occlusion due to Apidra. And now I load up a 300 unit cartridge and run it for 7-9 days without any trouble. I do change my infusion sites, however, every three days.

Woah. Glad I asked. May get up the nerve to try that. Thanks!

REALLY glad to know that. May have to talk to my MD…

No real problems with FIASP. Occasionally have a little tenderness when the infusion set in or a bump with soreness after removal. Never any stinging. The same as Novolog. the short tail with FIASP is so much better for me I’d change infusion sets more often rather give it up.

I actually hate the short tail and it’s caused me to try NovoRapid again. I think it’s a bigger problem on MDI since you can’t extend boluses or take more with the push of a button. The shoter tail is great for eating fruit and for quick corrections, but that’s about it I find. If I eat just about anything else I need so much more Fiasp and multiple injections after (unless I combine it with enough R) to keep from rising. I thought Fiasp would be great for MDI since no pumping issues/quirks to deal with, but wish there was a version of it that kicked in just as quickly and lasted as long as NovoRapid/log.


They added vitamin C I think

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Per Novonordisk PDF:

Fiasp® is
years of clinical experience,xi in an innovative formulation, in which
two excipients have been added, Vitamin B3 (niacinamide) to increase the speed of
absorption, and a naturally occurring Amino Acid (L-Arginine) for stability.


I’ve been trying to make the switch from Novolog to Fiasp, due to high blood sugars after meals. I just got a sample pen from my endo, and now see that it can only be administered in full, not half units. There are many times that for whatever reason, I only need .5, not a full unit. So I guess I have to purchase a vial if I really want to try it, and go back to syringes.

The other issue I notice from the forum is that it seems like a significant number of people find Fiasp to not work as well for them after a few months of using it. So they eventually return to Novolog or Humalog.

I’d appreciate anyone’s current thoughts about Fiasp, now that we’re in 2020 and it’s been awhile since this topic has been discussed.