"Stacking Insulin"

I'd be interested to read an explanation for this also. I experience the same thing with novorapid.

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Thats a bit strange you,d think it would balance to same effect! But I was told with my novo to take it with my 3 meals a day but not for snacks in between , to try take my snacks as close after my meal n include them in insulin, never got an explanation why! But this plan does not allow for an impulsive indulgent snack! Sorry not much help!


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I don't know the answer either. I use an insulin pump and if I have a snack a while after a meal it will take the insulin I gave into account when suggesting a dose to have with the snack. This is to apparently to avoid stacking but I don't understand the logic.


Neximus

tomvonc said:

My carb insuling ratio is 12g to 1u. Say for example I have 60g of carbs for lunch, I inject 5u of Humalog. All good so far. Then two hours later I decide to have a snack containing 25g of carbs so I inject 2u of insulin. Sounds ok so far. But this will usually result in me going a bit low. However, if I were to eat 85g of carbs at lunch, and i inject 7u of Humalog, I'm fine.
I'm not really understanding this. I've heard of insulin stacking, and I'm aware that Humalog remains active for 3-5 hours, but struggling to get my head around what is different about the two case scenarios I described above. Any explanations or advice would be most appreciated.

Tom

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Humalog mechanism includes a peak, when you take one dose (the 7u) you experience one peak; you 'stack' your humalog and you experience a double peak ( 5u peak then the 2 unit peak) and your bg drops even further... The shortest explanation I can easily pound out on an iPad...hope this helps. Cheers from the US

Just a thought - is it down to the type of food you eat at lunch and for the snack. I don't understand a lot of this but the fat and protein content can have an affect. It's sooooo hard getting it right at times !!

tomvonc said:

My carb insuling ratio is 12g to 1u. Say for example I have 60g of carbs for lunch, I inject 5u of Humalog. All good so far. Then two hours later I decide to have a snack containing 25g of carbs so I inject 2u of insulin. Sounds ok so far. But this will usually result in me going a bit low. However, if I were to eat 85g of carbs at lunch, and i inject 7u of Humalog, I'm fine.
I'm not really understanding this. I've heard of insulin stacking, and I'm aware that Humalog remains active for 3-5 hours, but struggling to get my head around what is different about the two case scenarios I described above. Any explanations or advice would be most appreciated.

Tom

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When you take the bolus it lasts for 3-5 hours. this is now called IOB (Insulin on Board). So if you think the bolus insulin lasts in your body for say 4 hours (as everyone is different) that would mean each hour is 25%. So if you have a snack after 2 hours after a meal. it will mean you have 50% of your insulin still in your body (IOB). The thoery is then that you should take 50% away from the next amount of bolus, so for a 25g snack, you should take 1 unit.

So in theory if you had a snack 3 hours after the main mean. It would mean your have used up 75% of the insulin and you still have 25% Insulin on BOARD (IOB) you would take 25% less insulin for the snack which would be 1.5 units

Now i am not sure if this works for everyone - but it is worth a try and see. - LET ME KNOW HOW YOU GET ON

So if you have a snack after 2 hours after a meal. it will mean you have 50% of your insulin still in your body (IOB). The thoery is then that you should take 50% away from the next amount of bolus, so for a 25g snack, you should take 1 unit.

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No, you are wrong - you crucially missed having to account for the increased BG. As a rule of thumb, 25% of insulin is used up per hour, and all the carbs will have entered the bloodstream by two hours... So in your case, you'd take 2u for the carbs - correction for insulin on board + correction for high BG.
If you eat withing 2h of the previous meal, you'd also have to add a correction for undigested food.

If the insulin doses are correct for the food you eat you shouldn't have to bother with these complicated calculations though (the idea that you'd need less insulin by having two sizes if bread an hour apart is absurd)

I'm not really understanding this

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That's because a carb is not carb, duh. Meal size, meal composition all change how it affects blood sugar. Sorry.

My understanding is that your background insulin should cover snacks of around 10-15 carbs without the need for injecting. I suppose in theory when you inject to cover the 25grams of carbs you snacked on, you actually may have only needed 1 unit to cover the remaining 10 grams that weren't covered by the background insulin.


Paul

As far as I make of it there can be "insulin stacking". I use Humalog, and on a basal bolus regime. I too have noticed that having a snack can cause more irregular bg's. When you have a snack, you basically end up with 2 doses working on one meal/snack.. It is like it makes the effect of the first dose greater (overlap = more effect) and also effects the 2nd even though on "paper" the doses and carbs match each other. The insulin follows a pretty set pattern of absorption for the person (excluding other factors such as exercise /heat etc) so ultimately it is going to make it harder to keep level if doses are more frequent. It isn't as simple as simply matching carbs to units of insulin.
As Paul above has said, yes I would too consider trying that...but you have to remember the 1 unit is going to be working all the time that it is supposed to and can then effect later doses as well!
I am at the stage of logging carefully what is going on myself, as my general adjustments have not always been going to plan!

Eat a low carb snack.....problem solved
A 2hr correction is insulin stacking, should you use the same ratio as that ?

tomvonc said:

My carb insuling ratio is 12g to 1u. Say for example I have 60g of carbs for lunch, I inject 5u of Humalog. All good so far. Then two hours later I decide to have a snack containing 25g of carbs so I inject 2u of insulin. Sounds ok so far. But this will usually result in me going a bit low. However, if I were to eat 85g of carbs at lunch, and i inject 7u of Humalog, I'm fine.
I'm not really understanding this. I've heard of insulin stacking, and I'm aware that Humalog remains active for 3-5 hours, but struggling to get my head around what is different about the two case scenarios I described above. Any explanations or advice would be most appreciated.

Tom

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I have a bit of a theory for this:

During the day you have hormones like glucagon present in your system which cause you to release glucose from your liver in a more or less steady rate and under stressful circumstances the amount of glucagon increases equaling more free glucose. The presence of insulin greatly inhibits the production of glucagon so having a normal meal and injecting insulin for about 4 hours you see reduced glucagon which returns as insulin eventually falls. However if you are "stacking" insulin for multiple meals and increasing the time of inhibited glucagon production for several hours, insulin becomes "more effective" in that there is significantly less free glucose being released from the liver as none is being released by glucagon and in practice you would need less insulin.