Wednesday, December 5, 2012

Apidra and the t:slim

UPDATE: Please see updated information at the end of this post. I think that I misunderstood the tubing interior. While what I state here about Apidra being the cause of my occlusions is likely still true,  as I've not had a single occlusion in the 2 months I've now used a different insulin (Humalog), I do not believe now that what I pulled out of my tubing was solidified insulin...

I started on the Tandem t:slim insulin pump in October, a little over 8 weeks ago. In that time, I've experienced an alarmingly unusual number of occlusions - blockages somewhere in the insulin delivery that causes the pump to alert the user with an alarm. From my third cartridge to now, I would say it has been 1-2 out of every 3 cartridges that I've had to change early.

All of these occlusions have resulted in extremely high blood sugars for a number of hours while I troubleshoot the problem, change everything out, and take a manual injection of insulin.

Two of these occlusions have happened while I was sleeping. The alarm did not wake me. I woke up a couple hours after the pump detected the problem, so several hours after the problem probably began, and only because I was feeling very sick. A high blood sugar makes me feel nauseous, sluggish, sleepy, unreasonably angry (rage hormones, cortisol), and very thirsty.

Anyway, like a good PWD, I've attempted to isolate the problem. I have spoken with the same two people in Tandem's (impressive) customer service on at least a weekly basis. I've spoken with my diabetes educator over the phone.

I changed cartridge and infusion set lots. It wasn't the cartridges or the infusion sets.

Tandem offered to send a new pump. I accepted. Three cartridges of insulin later, two of those three had occluded. It wasn't a faulty pump.
Tandem Tandems
That leaves one possibility - the insulin. It couldn't be the insulin, I thought. I've used Apidra fast-acting insulin since 2005. I've used it in pumps from Medtronic, Cozmo, and Omnipod. It couldn't be the insulin.

Now, there are plenty of anecdotal reports that Apidra seems to become ineffective on the third day in a pump. And any insulin begins to break down after it's removed from the glass vial. Apidra has never been problematic for me. Or at least I've never been able to blame any third day highs on bad Apidra. Apidra is technically contraindicated in pumps for over 48 hours, yet I've always gotten 72-80 hours out of a reservoir. Most people report no issues, so I've always just proceeded with cautious optimism.
The representative from Tandem's Customer Service told me that the t:slim was tested and approved specifically for use with Humalog and Novolog, and, while preliminary testing with Apidra showed no concerns, the majority of calls he personally was receiving regarding frequent occlusions all seemed to involve Apidra users. And diabetes blogger Sarah from Sugabetic mentioned to me on Twitter that she had heard people reporting Apidra turning to gel in the t:slim.

So, I had to get a-cutting. I split my occluded tubing from yesterday with a pair of scissors to find this crystalline substance inside it.

That's not part of the tubing. That's Apidra.* - please see update below
Alas, something about the t:slim cartridge and micro delivery chamber seems to age my Apidra to the point of a hardened substance. Like a pliable thread.

A piece of split, unused tubing looks like this:
sliced in half
My tubing looked like this, with an interior thread:
I've bent the tubing halves down like on an ear of corn.
So is this a piece of insulin in my hand? A PIECE OF INSULIN?*

I took great relish in taking a hammer to the opaque cartridge to get a glimpse at the interior reservoir bag. Upon impact, liquid insulin splashed all over my hands. This is what the bag looks like:
t:slim cartridge interior
The bag still has liquid in it, which at least verifies that it's a process occurring - insulin slowly turning to crystal as it moves through the system.* Perhaps it's aged by the materials with which it has come into contact. Perhaps it experiences some kind of catalyst from pressure in the microchamber. I don't know. I'm a shoddy scientist.

At the urging of Tandem customer service, I am switching to another insulin effective immediately. My CDE (diabetes educator) gave me a bottle of Humalog and a bottle of Novolog to try. I started with Humalog (an insulin I took from 1998 through 2005 and am familiar with). I've never tried Novolog, but I'll give it a go next. I don't expect them to differ.

The 3 Fast-Acting Insulins
I am just still in shock. I didn't think it could be the Apidra.

UPDATE: I have some facts wrong and need to issue a retraction. After cutting through additional tubing - both empty and with Humalog insulin inside it, I can state that the thread I saw is NOT crystallized Apidra as I originally believed. Inset tubing DOES INDEED seem to have an interior tubing piece that may be what I was seeing and pulling out. I had originally believed that inset tubing wasn't double-walled, but other pieces of tubing have proven that it depends on how one cuts the tubing. I apologize for the confusion I caused!


  1. I just MUST write my two year old post about this exact problem with Caleb and Apidra and OmniPod. Why have I waited so long? lol I have some nifty pics too. I hope Novolog treats you well!

  2. Amazing! A piece of insulin! Holy crap!

  3. Wow! What a science experiment!

  4. Piece of insulin - imagine! Grace experienced the same thing with Apidra and her Pod - magically on the 3rd day - voila - high BGs. Lorraine and I have spoken at length about this. We went back to Novolog. Excited that Lorraine will finally write about it!
    Good detetcive work, Melissa!

  5. Holy crap! You are--and this is--incredible. Why did no one test Apidra in an official way? Guess science doesn't have to bother testing it now--you figured it out IN YOUR HOME with CUTE BABIES all over the place. Wow!

  6. holy moly!! I've heard that Apidra is not recommended for TSlim, but never expected PIECES of insulin to be the issue! I don't even understand how insulins can differ so much from each other that one would harden in a certain pump while another remains in its true form. Weird!

    A. You are a science super sleuth (say that 3 times fast)
    B. I have never seen insulin in gel form
    C. I'm in shock & I still don't understand exactly how or why Apidra turned into gel in the tubing. That's crazy!
    D. I'm so sorry that you had to find out the hard way, but I'm really glad you found out

  8. So I just emailed this to a CDE in my office - and she's forwarding it on to our Apidra rep. YIKES BIKES. hope the logs treat you better!

    and thanks for telling us!!

  9. Those photos are crazy! I had issues like that (on humalog) using cleo sets a number of years ago. But it was only with those sets so i switched sets rather than trying other insulins. Glad you were able to figure it out!

  10. Whoa. I wish you luck with Novolog. Performance-wise, I saw no difference between that and Apidra in my old pump. I'm on Novolog because it seems to work best for me. Meanwhile, note to self, if I get a Tandem, DO NOT SWITCH to Apidra!

  11. I just recently switched to the T:Slim pump and I, too, had been using Apidra. The same exact thing was happening to me! After about 20 hours after my set change, I started getting occlusions. I couldn't bolus more than 2 units without an occlusion. My CDE gave me Novalog to switch to and my bgs have been stellar! I've already had to lower my basal rates!

    I was going to break open the last cartridge to see what was going on....but you did a great job! Thanks for your very informative post!!

  12. Wow. That's just... wow. I wonder if the tubing and infusion sets are made by Unomedical (just like all the other brand's sets are) or if they're made by someone else -- perhaps using a different chemical compound that somehow reacts with Apidra.

    As far as the Humalog/Novolog comparison goes, I believe Humalog peaks faster than Novolog does, but Novo leaves your system overall faster than Huma. I'd be interested to see what you find out.

    "Pieces of Insulin"... it's catchy. I think it would make a good title for a blog....

  13. I'm with you, having use Apidra for many years in a Cozmo without issue. I've had at least a dozen occlusions since starting on the Tandem. The Apidra documentation says it shouldn't be used for more than 48 hours in a pump...that tells me something.

    I'm switching back to Humalog. While waiting for it, I'm changing sets every 48 hours and that works fine.

  14. This is some seriously crazy stuff. One word of advice...Humalog works well for me, Novolog didn't. I'm not saying it won't work for you, and I'm probably an anomaly, but I wanted to warn you that it has a tail. It would make me crash hours after it should've been long gone. I would have loved to know that info BEFORE being forced to switch because of my insurance. Thankfully, I am now back on Humalog. Hope one of the insulins works better & doesn't crystallize. Please let us know how each works out. Good luck<3

  15. This is CRAZY on so many levels.

    My daughter used Novolog for 6 years...we had to change her settings a good bit when we switched to Apidra last year, because we had been accommodating for the Novolog "tail" without realizing it...once the "tail" was gone, her basals needed an overhaul around the clock!

    I hope you find smooth numbers and better pumping days ahead!!!!

  16. I had Apidra turn to gel in an airplane, TWICE (to and from my destination) and flights were less than 48 hours apart. That was my 'ah-ha' moment and then I found the Apidra literature online (section 5.7). Was also then informed of the Apidra not indicated for tSlim.

    Mine never got to the crystals you saw - that is super cool. Mine was a gel. It would come out of the luer lock (nothing coming out of site), but it wasn't dripping. I had a HUGE 'drop' of insulin but it wasn't dripping like a liquid. (this was on the airplane, both times).

    Before that, my daughter had a huge number of occlusions with Apidra in her tSlim. I had some. We changed to Novolog and have had no occlusions.

  17. Whoa! That's amazing! Don't tell Alecia, she'll start making insulin jewelry... Hmmm... :-)

  18. WOW! Like everyone else is saying, WOW! On a selfish level, I am kinda curious if I could cast it in resin (I blame both Scotts for putting this idea in my head). Glad you're ok. xo

  19. Holy Crap. That is INSANE. We have been using Apidra in the pod for about a year... And dare I say?? No problems. But I'm gonna do some sleuthing and see... That is CRAY CRAY!

  20. Wow. Wow. Wow. And I thought that I had seen everything.

    Just to add another voice: Novolog peaks slightly faster for me (YMMV). :-)

  21. Just popped in to say, Merry Christmas!

  22. I actually have less conclusions with Apidra than I did with Humalog. I was on Humalog for 12 years at the beginning of my diagnosis. About 5 years in, my A1c began to creep back up, and continued to creep up until I was at 9.5. At this point, I switched to Apidra, and quickly regained control over my A1c. In addition to Apidra being a great choice right after I switched, I am still under control 7 years later. I also find that Apidra lowers my blood sugar quicker than Humalog did, which is good for meals that I am unsure of the carb count, and must bolus after I eat. The issue with the T:slim pump seems like a pump issue, as I usually change my Animas pump every three days, and have only had an occlusion when I get my tube caught on the kitchen or bathroom drawer handles. Just my opinion, but I'm a huge Apidra fan.