Fiasp vs Lyumjev

I've been on Fiasp for 4 (?) years or so, and initially I was very happy with the much quicker action than my previous NovoRapid had.
No more prebolusing for 30 to 60 minutes, no more waiting for hours to see if my dose was correct before taking a correction.

However, Fiasp has become almost as slow as Novorapid was, and I often prebolus by quite a long time again.
My endo was happy to do a one off prescription for Lyumjev to see if this works faster, and I picked it up this afternoon.
So far, I've only used it once, and it appears it does work faster. However, it's too early to draw conclusions after one test, I could have been dropping already, or have overdone the last bolus before this, time will tell.

Does anyone have experience with both, and what did you find?

Also, Lyumjev seems to give me an itchy kind of sting, is this common?

Any tricks to remember if I dosed or not?
The Novopen 5 I use for my Fiasp has a memory for last dose, which I use at least once daily.
I always log my bolus in my Libre app before injecting, but I often find I'm wondering if I actually took it 10 minutes later, being able to check on my pen is such a help!
Having to go without this feature is not something I look forward to.

Any other thoughts welcome as well of course!

Wow, thanks @Finnlee , so much to think about!

Finnlee said:

I haven't noticed a slowness with Lyumjev, but I do use it in conjunction with NovoRapid (NovoRapid in my pump, Lyumjev as manual injects), so maybe that's enough to keep my system on its toes and not allow sensitivity to wane. Prior to switching to a pump, I used Humalog and Lyumjev together as MDI.

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I was already thinking about using both, and might do some experimenting with this. I already use two basal insulins (Tresiba and Levemir) already, no reason to not use two bolus insulins as well. And I have enough of both at the moment, the trial turned out to be 5 disposable pens on top of my quarterly issue of Fiasp penfills.

Finnlee said:

Sometimes Lyumjev gives me a little sting, but I can't tell if it's the insulin, the needle or the exact spot I injected into. It's not too bad for me and goes away after a few seconds, so it's not a reason for me to stop using it.

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The sting might even prove useful. With my so far one dose of Lyumjev the sting stayed for some 10 minutes, which clearly told me I hadn't forgotten to inject. Time will tell if that sting is enough to make me not want to inject though.

Finnlee said:

I don't have suggestions for remembering if you dosed, but until you find something more practical, could you put the dose through the (empty) Novopen? Just to keep it as a record of when you last injected, even though it was through a different pen.

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Very creative, and it might even work with my quirky brain. Inject Lyumjev and immediately after dial up my empty spare novopen to have it show the dose. I never would have thought of this, but if it looks like I like the Lyumjev I'll give it a try!

Lilly sadly discontinued the pens with a memory (not the HumaPen Savvio but the HumaPen Memoir). An alternative would be a Timesulin cap if I can get one.

Finnlee said:

Are you using disposable or reusable pen for the Lyumjev? I don't know if the Lyumjev reusable pen (HumaPen Savvio, I think) has a dose recorder on it. I don't think that reusable pen comes in half units, but the KwikPens do, if that's something that would be useful.

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For now, disposable pens. It's only a trial so it would be a waste to have my insurance pay for a pen I won't use. No need for half unit pens in my case.


My findings so far seem to be interesting, but more experimenting is called for before I'm sure about how the Lyumjev acts for me.
It did seem to act quicker than my Fiasp and gave me a hypo 4 hours post injection. But so far, no way to tell if it's just one of those days I needed less insulin for the same beer, or if it's that the Lyumjev behaves differently.

RD02 said:

Well I’ve done a few bolus with Lyumjev in the Omnipod 5. It’s very early days so far, but I have noticed already a significant response time.

Before I was actually using Fiasp and found a need to pre-bolus before a meal, but no more than 15 mins. This morning eating my exact breakfast porridge oats, normally this would spike to max 9 mmol within 45 mins of consumption with a pre-bolus of 15 mins.

Same breakfast/ same insulin amount no pre-bolus and maxed out at 7mmol 45 mins later, and even better still back to its start level of 5.7mmol within less than 2 hrs.

So far I’m impressed, time will tell. I have 1 vial on trial, if it continues like this will be swapping to Lyumjev.

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Hi @RD02 , I took your post here from this thread: https://www.diabetes.co.uk/forum/threads/lyumjev-insulin-and-pumps.202163/post-2677233
I'm not on a pump so I didn't want to derail that thread.

Looks like we're in similar boats (except I'm on pens).
I started a trial of Lyumjev instead of Fiasp yesterday evening. Too early to be sure, but my first impression is that it works faster than Fiasp.

I only dosed twice so far, first dose was for two Belgian beers. I usually (Fiasp) prebolus for them by 45 minutes or longer, and still have to watch the speed of drinking to avoid spiking.
Yesterday I thought to be careful with the Lyumjev and only prebolused by 15 minutes. I did manage to avoid going low, but it sure meant I had to up the speed with my beer.

Didn't inject for my evening meal because a low was still threatening, and there were little carbs in my meal although I would normally have taken some insulin for it. I started rising a bit a while after dinner so I took a small correction. Corrections usually take ages to work for me, seemed much faster this time.

Will try without prebolusing today and see what happens, and I hope you'll keep sharing your findings as well. Very nice to have someone make the same switch at the same time!

RD02 said:

For me it’s working quicker than Fiasp and has taken off at least 2mmol from spikes in food. Porridge oats in the morning would normally hit 9.5 before dropping. Lyumjev flattens it at 7.5. I’ve noticed it seems to trail off quicker in being active, so it appears less forgiving for underestimating carbs, and if you mess up with the dose, by god do you need to throw in some quick acting carbs.

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By now, I've found I still need to prebolus, but not by as long as with Fiasp. And yes, like you, I've had more lows or almost lows due to learning to work with it.
It's a slow learning curve as I generally eat low carb (except for those beers), so other factors have a relatively large impact on my BG which makes it harder to see what is what.

I don't like the slight sting, but it'not bad enough to decide against it.
I really miss my novopen 5 with the little memory display, and I don't like the 'feel' of those Lyumjev pens at all. Which may together with the stinging make me decide to stick to Fiasp, despite its slower action.

No hurry though, the trial was for a box of 5 pens so I'll use them up either way.

EllieM said:

They don't have it in reusable pen format?

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They do, but it's only a trial so it would be a waste to get an expensive reusable pen.
The reusable pens don't have a memory function though, which may be the dealbreaker for me, I use it a lot.

Should I decide to stay on Lyumjev instead of Fiasp, I will of course request a reusable pen instead of the prefilled ones.