Hi all, I have a question for those of you who use Novolog, specifically in a pump. I have used humalog in my pump for the past 10 years but was forced to switch to Novolog this year when my insurance stopped covering humalog. I have heard that Novolog perhaps has a quicker onset and/or shorter duration of action than humalog, but I’ve only been using it for a few months, so it’s been difficult for me to tell. However, I recently started using the Dexcom cgm and now that I have a ‘visual’, it seems that I will drop quickly at 1-2 hours post-bolus/correction and sometimes I will eat something because I feel like if I don’t, I’ll bottom out with 2 more hours of active insulin. But when I do this, I will see a rise in BS that either goes way back up or at least doesn’t come down or level off at all when I supposedly have 2-3 hours of active insulin remaining. So my question is this: have those of you using Novolog noticed that your active duration is shorter than the standard 4 hours? I asked my NP about this and she maintained that 4 hours is still a good limit for Novolog, but I’m wondering if 3 hours might be more accurate. I’m feeling frustrated! Thoughts?
Hi Shelby: I started off on Humalog when it first came out. Then, several years ago, my insurance switched to Novolog. I actually did not see any difference--I know some people do, but I didn't. However, I use a duration of 3 hours--4 hours is way too long for my response. Then, to complicate matters, my insurance is now switching to Humalog. I will watch my CGM closely!
I have my duration set for 3 hours on my pump but per my Dexcom there’s actually a little tail my duration is more like 4 hours for me but the 3 hours works better as far as my numbers go so I keep it at 3. I have noticed no appreciable difference between Humalog, Novolog, and Apidra.
The only time I’ve had to make an adjustment like that was when I switched from Medtronic to Animas I found that I had to cut my basal rates by about 10% pretty much from the get go in order to keep from crashing. My bolus settings stayed the same though.
Diana, that is good to know and interesting about the change in basals on switching from MM to Animas, as I am getting ready to do that myself in the next couple of weeks! How have you liked the Animas pump versus the MM? Thanks!
The duration of insulin action, I believe, will vary from person to person within a fairly tight range, like 3-4.5 hours. I also believe that it varies in the same person with respect to time of day. While reports of other's experience may be useful to you, the best way to gauge your situation would be to test it out.
I've been using a Dex CGM since 2009 and caution you to not over-react to its indications. I have seen rising or falling trends moderate quickly to a sideways arrow, sometimes even reverse directions. Your report about the 1-2 hour post bolus/correction can be misleading. I prefer to watch a situation like that without taking immediate action. Often times the situation will resolve nicely without any further action needed on my part.
One action you could take is to do a finger-stick BG. I almost always use a finger-stick before I add insulin or carbs. While I love the consistency and accuracy of my Dex, it is far from perfect and I can't trust it 100%.
I know the temptation to act that probably influenced you to add extra carbs. You're looking at a post bolus number on the CGM that may be 100 and you also observe a relatively high IOB number, for example 5. The wild card in this equation is the status of your digestion. How much of your meal has already been metabolically processed and how much is pending? Did you eat a meal high in protein and/or fat? Was there a lot of fiber? Or did you consume a large % of carbs? It's hard to know the exact % of digestion completed, except to guess based on your past experience.
My experience with insulin duration has been mistakenly (for me!) setting the duration too short. Then I get unexpectedly whacked by the insulin tail and go hypo 3-4 hours post bolus.
I've used Humalog, Novolog, and Apidra in my various pumps over the years. When I switched from Novolog to Apidra a few years ago, I shortened the insulin duration on my pump too much and got hit with 3-4 hour post bolus hypos (a pattern, not just one instance). I would recommend that you play with this duration setting and see how it works for you. As with any experiment, it's important to write things down. Life is busy and it's hard to keep track of all the details ;- ). Good luck. I hope you enjoy your Dex as much as I do. Do you use the Dex software?
I agree with what Terry wrote. I find if I have a snack after a "lower" post prandial I often overdo it and it shows up later as a high.
Thanks, Terry and IL71. I definitely feel the lows and never treat based on the Dexcom. I always test, but it’s seeing that large IOB that gets me every time, so waiting it out isn’t always a comfortable option, you know? I am brand new to the Dex, so I only have a few days worth of data at the moment, but I look forward to using the software for a better big picture. Thanks for your insights.
I’ve been happy with the Animas pump. I ended being allergic to the Medtronic sensors which was the primary reason I switched.
A couple observations by snacking at 2 hours it’s going to make it difficult to fix your insulin to carb ratio if it needs fixing.
Also given how both Animas and Medtronic calculate IOB in a curve linear fashion at 2 hours there will still be a fair bit of insulin on board but it’s going to start dropping off fast. In other words your blood sugar may not actually drop as much as you think it might because you’re well past the peak action of that bolus unless you extended it.
Keep in mind that it’s possible you’ve been doing this all along you just didn’t know about it because you didn’t have the Dexcom to reveal it to you. That’s one thing I’m appreciative of with the Dexcom is just how rapidly blood sugars can change and it’s made me aware of how much I was missing even though I was testing frequently. In the past have you needed to snack 2 hours after bolusing in order to keep from going low?
I had the same problem when starting the Dexcom. Without my Dexcom I usually looked pretty heavily at my IOB. Now with the Dex and seeing the patterns that I do I rely LESS heavily on my IOB and MORE heavily on what my Dex is showing. Like Terry in most situations the Dexcom shows me that the quick drop usually levels out before hypoglycemia. But, it is hard to expect that to happen when the Dex is showing a straight arrow down at 120 mg/dl with 4 units IOB eh? I finally just told myself that this is the reason I have the Dexcom is to let things like that ride until I see something that is definitely going to mean a low soon (more like 80 and heading down...).
As far as IOB goes, I noticed that for me, it needed to be on 3 hours when using Apidra but more like 3.5 to 4 hours using Novolog and Humalog. I have heard less people notice a difference between Humalog and Novolog as opposed to either of those vs Apidra. Apidra seems to have a slightly quicker peak (not so much I notice a big difference in post prandials) with a smaller tail. As others have pointed out there is such a difference between different people your best bet is to test it out.
It is also important to remember that while pretty much all pumps will compensate for insulin stacking when doing correction and bolus calculations, as far as I know, no pumps handle carb stacking. So if you still have food remaining to be digested and absorbed, that will be ignored when doing a correction or meal bolus calculation. So with snacking after a meal, this also can lead to highs since a pump will not count insulin on board against "carbs on board."
At 2 hours post meal, when faced with a high IOB and a relatively low BG, and my CGM has a recent history of strong correlation with my finger-sticks, I like to think of a finger-stick BG measurement as a "sneak-peak" as to what the CGM will display in 15-20 minutes. If the IOB, BG, and post meal time combine to create a nervous situation, a series of strategically timed finger-sticks can instill confidence and prevent unneeded treatment that's often regretted later. It's like forward looking radar that illuminates the near time horizon.
It's a game we all play while trying to pay attention to the rest of our lives! Most people have no idea what we do "behind the scenes."