Stacking Insulin

We all know that "stacking insulin" is to be avoided. I've experienced insulin stacking and had fast, severe lows from correcting too close together. On the other hand, if I have a stubborn high, I don't want to wait any longer than I have to for it to come down.

But this is where I get confused and can't find a definitive answer. What is considered too close together to correct? I've had stacking episodes when correcting after 2 hours so I avoid that. I've successfully corrected at 3 hours but then will sometimes go low several hours later. What is your experience and how closely together do you correct?

I recognize that you should take into account insulin on board but that concept seems to not work well for me because I always end up with not enough insulin when I assume that the insulin on board is used up evenly during the duration of insulin.

Is an insulin bolus for food considered stacking if you've taken a correction two hours before? Say you ate dinner and bolused for dinner and an hour later decide you want coffee and dessert...would that be stacking since theoretically the carbs would offset the insulin? I guess the danger is in the accuracy of the I:C ratio and carb counting?

I've read Pumpin Insulin and the theory but I'd be interested to hear your practical real life take on corrections and carb boluses relative to insulin stacking.

I too correct a stubborn high by stacking insulin. I just deal with the lows because I'd rather have a low than have a prolonged high. I found that the best remedy for a stubborn high however is a vigorous 30 min. walk. (but that's not always possible)

If your I:C is good most of the time your carb insulin is covered buy food but you must figure out how long your insulin stays active and use this time frame for correction insulin calculations.

Example: Your insulin lasts 4 hours and you add correction insulin to a meal bolus and you do a correction 3 hours later there is still some active correction insulin so you will need to subtract your active correction insulin from the new correction bolus. When I was on MDI I used 4 hours and subtracted 25% of my active insulin every hour. This is not a active insulin curve like Minimed and JJ pumps use but it's better than nothing.

"Theory and Practice never got married" :) Amen to that. Thanks Alan!

Hi John, I've been using 4 hours (for Humalog) but it almost always seems like it doesn't correct enough. I'm pretty certain the duration for me is much less than 4 hours because I come down more in the first 2 hours than I do in the last 2 but I read on another thread here that the duration is always the same for everybody so I'm a little stumped.

We find prolonged a high always takes almost double the insulin suggestion to correct and if were not aggressive to start with, then we wind up stacking too. Also resorting to insulin by shot instead of pump by the 3rd correction. We try to catch them early, since son wears a cgm, so as soon as he shoots up and we see it plateauing high, and if the meal had a significant amount of protein and fat we start hitting the buttons!

Thanks Emily, I try to catch them early too but I tend to be impatient and correct while it's still on the way up before it plateaus...but many times my dosage isn't aggressive enough because it's on an upward trend or insulin resistance. Argh!

Then my question long do I wait to correct again when I can tell an hour or two in that it's not enough insulin?

I think it depends on what's coming next. If I were sitting around the house in the early evening, and it's been three hours since my correction, and I'm still way too high, I might sneak in an early second correction. However, if it's only been two hours and I'm getting ready to do to sleep, I might just ride it out until morning -- or set the clock for four hours and do a tinkle/test/correct break before going back to sleep. I wouldn't dare stack before a long drive, a job interview, a performance. I might risk it if I KNOW that I can test every half-hour to hour and there is no heavy machinery involved.

I've only been doing this since just after Christmas, so I don't claim to have a lot of expertise. If I've made a correction and want to eat a little while later, I do take the insulin on board into account when I calculate the amount for the bolus. I used Humalog and while it's supposed to last 4 hours, for me I think it's closer to 3-3.5 and so I factor in 33% per hour. That's worked well for me, so far.

I'd like to know too, wait you have 27 years exp. to our 2+. Cgm helps but we removed it yesterday and he wanted a break (a day usually) and we didn't catch his high before bed. The correction suggestion .06 gave 2 units for 216 (@ 2 hour mark) and that was about what he was this morning! Arggghhh! Why if he goes to bed around 100 he can wake up around 100. But if we try to correct a high during the night, it usually stays high?!!

I have lots of years in but that doesn't mean I have answers.. ;) I always feel like I'm still learning with this disease or at times maybe relearning if it's an issue I haven't dealt with for awhile. Plus I like to see how everyone else solves the same problem.

I know it's caused by insulin resistance and/or pulling the trigger early while it's still going up which causes too little insulin to be delivered. But it's either wait it out or shoot again and I'm scared to overdose. In most of my 27 years I didn't have as many stubborn highs as I've seen over the last year nor did I have the tendency to drop really fast so I'm sort of in a catch-22.

That's so true, and it's what so great about TuD is learning how everyone else solves the same problem. We all have to deal with it and some have different approaches given their variables. Nate had also had a high after school yesterday, right when he had planned to have a snack (cgm had had ??? at that time) so we gave a large correction (incorporating some of the snack too) AND I told him to run on the trend mill for 15 minutes. Bolus to recheck was about 45 minutes and he had dropped 132 points. IOB and exercise is a powerful combo! But you can ask him to do the before bed, especially without the cgm. If this was an exact science and we weren't dealing with other hormones that we can't predict, you'd have this mastered and we wouldn't need so much advice! :)

Also your correction factor needs to be accurate, and no, I think the duration varies between the three fast acting insulin and even somewhat for people individually.

I think we all tend to use the word "stacking" differently. I use it as a bad thing: you don't want to stack your insulin because then you risk bad lows. But I don't consider it stacking if you accurately take into account the insulin on board. Some people just use it to mean using more insulin when there is still insulin at work, by which definition, yes, I stack.

I always correct if I'm high at the two hour post prandial mark, unless of course I'm not that high and there is still sufficient insulin on board to bring me down. That happens if I'm say in the 150's. It is a lot easier to do all this computation with a pump wizard because it computes the insulin on board accurately and not as a straight across the board formula. But I did ok with that when I was on MDI.

But whether MDI or pump (which uses, of course, the numbers you've programmed in!) you have to input correct data. The Durations of each of the 3 insulins are listed on their inserts, but individuals can vary. I use Apidra and the 3 hour duration is pretty close to right for me. You can test your duration of course. Also the ISF has to be accurate, and after 3 years on insulin (one on a pump) I'm ashamed to admit I just got that my ISF varies between daytime and night time.

I generally will test after correcting and will usually wait two hours to correct again (keeping track of the IOB of course). Unless I am extremely high (over 250) and there's been little movement in an hour, because at those ranges and higher it just takes more. I agree with Jean that it all depends on time of day. I will be much more conservative closer to bedtime. I live alone and would much rather wake up high and worry about it in the morning, then go low and not wake up at all.

I think prompt correcting is the single factor that most has allowed me to get a 5.7 A1C, because what counts (in A1C, but more importantly complications) isn't how high you spike but how long you stay there.

LOL Are you by some chance a lawyer, Alan?