I’m trying out this insulin patch which has a 3 day wear time.
My question is how long does it take for insulin to degrade when you have a pump. Has anyone kept their pump on longer than the wear time with insulin still being effective?
I ask because the patch holds much more insulin than I use in 3 days so I was wondering how long I can go before patch is changed and a new patch is put on with fresh insulin. Thanks.
3 days is generally recognized as safe in the diabetes world. Insulin degradation is a continuous process, so it’s a bit of an arbitrary line in the sand. Body temperature has very little to do with it. It’s more to do with how easily the volatile preservatives like to escape. They can actually evaporate through the plastic. Without the preservatives, the insulin molecules start clumping together. Not only does that make them less effective, but it can also clog up the works so you stop getting any insulin at all.
That said, what the manufacturers recommend and what we get away with are two very different things. Anecdotally, you’ll find lots of people who use insulin longer than that. It’s pretty common with traditional pumps to fill a reservoir with as much insulin as it will hold and use it until it’s gone. That could be a single day or even a week or more. Entirely depends on how much insulin that person is using.
Tubed pumps have an advantage, though, that you do not: the ability to change infusion site. That’s actually going to be your biggest concern. Degrading insulin ABSORPTION, not the insulin itself degrading. See, our bodies like to try and destroy the invading cannula. When they can’t kill it off, they erect a wall of scar tissue around it. It’s kinda our last line of defense. Once that scar tissue is up, insulin can’t get through, leaving you in a dangerous situation. Scar tissue can also take years to break down, so the more you develop, the less real estate you have to deliver insulin. A very common problem amongst long-time pumpers.
Again, 3 days is generally recognized as safe before the immune system starts building that scar tissue, but there’s some variability in there. There are people who can only get 2 days and others who can go 4 or longer. We can’t tell you how your body will behave. That’s up to you to test for yourself, if you choose. Just be aware that there could be long term consequences to running a site longer than recommended if you’re not absorbing the insulin you deliver and/or you’re not able to use that location again for years to come. The idea is to change the site BEFORE you notice any issues. If you try to push the wear time and notice your insulin isn’t as effective as it usually is, or is slower, then you’re pushing your luck.
I have tired to get to 4 days but it usually craps out at 3.5 days.
I usually go 3.5 days. Beyond that, I think I start seeing the insulin becoming less effective, but it’s not a strong tendency, so I may be wrong.
The reason I try to go longer than three days: my 'script says “three days.” But then I can run into a couple of problems: (A) if a set goes bad too often, I could run out of sets before I can get new ones. (2) If I’m going on a long trip, I may not be able to get sufficient sets to cover the trip before I leave. Changing every 3.5 days allows me to build up some extra sets to cover these potential problems.
Don’t tell Medicare!
—Keith
I go about 6 days because that’s how long it takes me to use the insulin in the pump’s reservoir. I think Robyn’s point is more relevant, though. I change my site two or three times during that period when I’m using up all the insulin in the pump. The site will give out before the insulin will significantly degrade IMO.
This is the key effect. Insulin absorption is what matters. When absorption is working, glucose levels respond. Insulin absorption, however, is not only a function of good infusion site mechanics but also by other influences including counter-regulatory hormones like cortisol and adrenaline.
I only use about 25 units of insulin each day but I fill my 300-unit reservoir to full each time. I independently change my infusion sites every three days but the cartridge and infusion set remain. I have not noticed any functional degradation of my insulin supply quality over its 10-12 day residence in the supply cartridge/infusion set. I use Apidra insulin in a Medtronic cartridge and 43" infusion set.
I’m basing my judgment of the quality of the insulin absorption on the quality of my CGM glucose control. My glucose control is not static and does vary, influenced by many factors but it does exist in a reasonable range. Time in range is the best indicator for me and I use a tighter than typical range.
I only offer my experience as an anecdote and do not infer a more generalized meaning.
Thank you all for your responses. They were all very helpful. I have found this patch to work for about 4 days. After the 4th day, my blood glucose started to climb so I changed the patch. My blood glucose then stabilized.
I’m on MDI, but my endo gave me a starter package of these patches so I thought I’d try them. This is what prompted my question as I’ve only ever done injections using insulin vials when I was first diagnosed to then using insulin pens when they became available.
My schedule is exactly the same as yours. Trying to reply to Tnyc but it keeps going elsewhere.