Mixing Fiasp with Novolog for pump use

I was recently given a trial of Fiasp to use. I know it’s not supported to work on the tslim so I’ve just been injecting it manually when there is a high I need to correct and find that it’s much more effective correcting a high than novolog is. Because by the time novolog kicks in, the BG would have gone even higher and I find myself continuously trying to bolus more and more. But with Fiasp, it turns it around quickly.

I would love to use it in the pump but occlusions are a problem. I also heard that for some people, Fiasp 's effectiveness wears off after a while. But some people have reported mixing Fiasp with Novolog makes the occlusions go away. I’m wondering how many people here do this and whether it’s been effective for you?

I’m interested in particular:

  1. When you mix it, what ratio do you mix it?

  2. What is the pre bolus time after mixing?

  3. Do you tell your doctor you are doing this and what do they say? :sweat_smile: My doctor doesn’t keep up with diabetes approaches and I’m pretty sure he won’t support mixing insulin. I don’t even think my endo would approve of it because it is not “by the books”.

I’d start out simple: try just Fiasp in your pump. It may not be approved for the tslim, but that really doesn’t matter; lots of people are pumping with Fiasp, approved or not. Occlusions are a problem for some, but I don’t think they’re overly common, since (see above) lots of people are pumping with Fiasp. I used it for a couple of months in the Omnipod (when unapproved for pump use) and did not have any occlusions.

If you’re not happy with Fiasp on its own, then you could try mixing. Or use a combo of Novolog in your pump and Fiasp by injection. That is what I do, with Humalog and Fiasp, as it allows me to customize the amount of fast-acting to suit the meal I’m having, rather than being constrained by a pre-mix.

You could put off telling your olde worlde doctor until you have stellar BG results to show him.

1 Like

From what I know and have heard ,
You will have occlusion issues if you have basal rates under .5 units per hour.
If you are less than that then mixing it is probably a good idea.

Hey it was free so you aren’t really losing much by trying it. Just have new set and cartridge and humalig with you in case you need to switch

1 Like

On my Medtronic 670G andGuardian sensor, I have been using Fiasp for about a year. Perhaps on two occasions I received alerts regarding occlusions. I often go for 2.5 hours at minimum delivery (well under .5 units) and receive a warning; however, without receiving an occlusion alert.

1 Like

If it’s not an occlusion alert, then what warning do you receive? :confounded:

If you do an advanced site search for “fiasp” in the search field and either @Paytone or @Jim_in_Calgary in the user field (the only two I could remember off-hand doing such mixing), you’ll find plenty of results talking about mixing them. Unfortunately, some of those threads are long, hence the not linking directly myself.

A 50/50 mix is what I see being done most often, but seems @Paytone was doing 80/20 at some point.

1 Like

My basal rate is above that but when i do extended or temp boluses, it may be under 0.5

Great thanks, I’ll go looking

When you are at minimum delivery for 2.5 hours, the 670G/Guardian 3 system alarms and requests you to enter a new BG reading to be sure everything is working properly.

Does anyone know whether you can use fiasp or a mixture of it with control iq? I wonder whether the algorithm takes the time it takes the insulin to work into account and given that novalog and humalog are the only approved insulin, it factors in 20 min delay into it so that if using fiasp, it wouldn’t work because it’s faster

Officially you can only use novolog or humalog. But many people use others and varying mixtures.

1 Like

I have a similar question as @tedos. Is the Control IQ algorithm based on the FIASP or NOVOLOG, i.e. insulin available upon injection (FIASP) or a 10 to 20 minutes lag (NOVOLOG)?

In my two months use of Control IQ, BG does not drop until 15 minutes after NOVOLOG injection. I assume that BG would drop quickly ( if not immediately) after FIAP injection initiated by Control IQ. Is FIAP a better choice for pump?

It is currently based on Humalog and Novolog, the only insulins “approved” for use in the pump. It doesn’t matter terribly much, though. The duration of insulin action isn’t all that different between them. It gets into the bloodstream marginally quicker, but lasts about the same. That means the first 15 minutes of IOB might not read 100% true, but Control-IQ isn’t really making any adjustments that close to a bolus anyway. It may still decrease your basal or stop it if you’re trending low, but it can’t otherwise significantly change your insulin delivery in that small amount of time

Also, we’re expecting a software update soon for Control-IQ. They’ve promised more customization options, and I suspect an adjustable DIA will be among them, along with the ability to set a lower target BG.

I know that only Humulog and Novolog are approved for pump use by pump manufacturer.

If the C:IQ algorithm is based on Humulog and Novolog, there should be a time delay (10-20 minutes) for seeing the effect of Bolus insulin. But, I am not sure whether the program coding includes the time delay. I would like to say, there is no time delay built-in for coding simplification.

For those pumpers who use FIASP, do you observe BG dropping sooner than using NOVOLOG?

1 Like

I don’t. My cgm arrows go from dreading** to trending down on the 20 min reading for both fiasp and novolog

**EDIT - I mean steady… it autocorrected to dreading :smiley:

@tedos Dexcom G6 arrow direction does not change until after receiving 3 BG readings (or 3x5 minutes= 15 minutes.) It only show a trend after 3 BGs.

However, if you turn the Smart Phone side way, you can find out the actual BG readings. Sugarmade APP indicates BGs with + or - N (increase or decrease) from the last reading. You may be able to tell whether FIASP responds quicker than NOVOLOG.

No I mean I don’t find a faster response with Fiasp. Both display similar behaviours for me and similiar BG changes. I know when the insulin has kicked in when my arrows go from stable to trending down - this usually happens for me on the 20 min mark (4 dots)… sometimes on the 5th dot.
If fiasp was responding quicker, I would have expected the arrow to trend down before the 4th dot (20 min mark).