So Long, Symlin


Syringe with insulin and SymlinAh, Symlin. You were fun. An interesting game of self-experimentation. You kept my post-meal blood sugars so slow, so graded.

But our shared days and nights are over. You changed, and I found myself wistfully wanting the drug I chose originally, not the new version– bigger around the middle, with a lot more packaging all over.

I think my metaphor has escaped from me, so I’ll say it outright: Amylin stopped making the Symlin vial, and the switch to the Symlin pen rendered it useless to me.

I had been mixing Symlin with my insulin (shh, don’t tell!), and that was working capitally. Then the pharmacy informed me that I would have to switch to the pen, as the vial had been discontinued. No sweat, I figured– I would just keep drawing the drug out of the pen with a syringe.

But there was a catch: the pen Symlin is not the same as the vial Symlin. The active drug is the same– pramlintide– but the pen is a more concentrated formulation.

And that’s fine for most people, assuming their doctors adjusts their dosings accordingly (the pen, notably, is dosed in micrograms instead of units as the vial was, I imagine in part to force patients to get the amount re-calculated). But, if, like me, you try mixing the more concentrated solution with Novolog insulin, you will find that the clever mix no longer works– the insulin precipitates out. The smallest bit of Symlin, and my insulin cartridge became a cloud of white powder, suspended in liquid.

At first I thought it was just bubbles or something, but my absorption definitely suffered. It was precipitate. My insulin was stunted, rendered useless by the Symlin mix.

I could fix this– I would just have to add a buffer (sodium acetate, likely) to the Symlin to return it to its original concentration. Then I could mix to my heart’s content.

But then we’re talking mixing insulin, Symlin, and a buffer, which is no longer a quick-and-easy deal. Loading an insulin cartridge takes me 3 minutes; mixing Symlin and insulin and loading a cartridge, ten minutes; three solutions requiring precise titration? Eh. Symlin was nice, but my post-meal spikes aren’t so bad as long as I watch what I eat, which I do regardless.

So convenience wins. Sorry, Symlin. You’re just not the drug for me anymore. This new you is too intense for me. Maybe, if you age a little, return to your old, easy-going self, we can talk again.

In the meantime, I have to re-learn to dose insulin without Symlin, which means more waiting after bolusing and smaller boluses. Adjust, adjust, increment, increment– story of a diabetic’s life.

Symlin and Insulin- Friends no longer.
Symlin and Insulin- Friends no longer.
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Stefanie Tsabar
10 years ago

I love the thought of you standing in your lab coat, squirting this liquid here and that liquid there, test tubes bubbling over, small fires in the background… and all this in the comfort of your bedroom.  Sorry to hear that your mixing days are over, but just think of all that extra time you’ll have now…!

Dr. Margaret A. Morris
10 years ago

@Scott Disproportionate only if you don’t scale for our level of understanding of each process; we don’t understand enough about the continuing immune attack on beta cells to make simply funding a bunch of trials effective right now. Instead, we need to continue funding the basic science research towards understanding beta cell replacement (either via transplantation, encapsulation, or regeneration) as well as towards understanding the immune dysregulation that characterizes diabetes. And that, thankfully, is being funded by the NIH/NIDDK, JDRF, and others… though of course more funding is always appreciated ;)

Scott S
10 years ago

That’s interesting that Amylin chose to stop selling Symlin vials, considering I was under the impression they were pursuing trials to use Symlin in a bi-hormonal pump trial of some kind.  I don’t know if this is still on the trial agenda, but I believe Amylin is also pursuing some kind of trial with Humalog (insulin lispro rDNA origin) premixed, which is a bit concerning considering that the titration schedules for everyone is slightly different.  Oh well, maybe someday they will realize that all these efforts to replicate functional beta cells would best be replaced by … well, actual beta… Read more »

10 years ago

Bummer! I was really interested on how this worked when I first heard about it.

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