The Great Vial Experiment

I use very small doses of basal insulin. No more than 2.5 units a day.

But though I've been able to make an insulin pen last long enough to use up every drop of insulin in it, my experience with vials over the past several years has been that the insulin in them always goes bad, no matter what I do to try to keep them alive.

I've tried all of the following: Alway using a new syringe, wiping the top with alcohol, and refrigerating the vial with a thermometer near it to make sure it isn't getting too cold. It doesn't matter. Insulin from the vial always starts to weaken after about six weeks and my blood sugars start creeping up. If I get a new vial, it's immediately very clear how weak my old vial was and if my doses have been creeping up I can have an interesting day the first time I use the new vial.

Pens don't do this even when I reuse pen needles, and my guess is it has something to do with the pressure inside the pen which pushes anything in the needle out before it can enter the insulin container and contaminate it.

Whatever the explanation, my current insurer charges the top copay--$50--for a vial of the kinds of insulin I'm using and won't cover pens without a long and complicated appeal put in by my endocrinologist. I don't like to use pens for the basal anyway, as I use fractional doses and I don't trust the pen to dispense 1 unit accurately. So when I bought my latest expensive vial of Levemir, I decided to try an experiment to see if I could keep the insulin in the vial alive for a longer time.

What I did was mail order some sterile 10 ml vials and transfer 100 units of insulin into the new sterile vial. I'm going to draw the insulin from that sterile vial, not the manufacturer's vial and thus cut way down on the number of times I introduce a needle into the main vial. Hopefully this means I'll be able to use all of those 1,0000 units instead of only 150 or so.

Another benefit of this approach compared to pens is that I won't be wasting the many air shots I have to waste when I use pens. The air shots can use up even more insulin than my basal shots. The convenience of the pen is a huge issue with post-meal insulin, but not for basal.

I'll be reporting back in a few months about whether this strategy is effective. If any of you who use tiny doses have any other suggestions about how to keep insulin in vials alive. Let me know.

UPDATE: 5/24/08

The insulin in the mail order vial is still working as it should. The only problem I've run into is that my syringes are dulling out much faster than they do I've been reusing them with a manufacturer's pen. This is probably because the rubber seal on the mail order vial is made out of a cheaper material.

The result is that the shots will hurt and bruise if I don't change the needle after no more than 2 shots.

NOTE: I have tried not reusing needles and reusing needles and have not seen any difference in how well my insulin holds up. When I reuse a syringe I do not inject air into the vial and I carefully expel any insulin left in the needle squirt-gun style after each use. Periodically I bleed the air out of the syringe by inserting a new needle with the plunger removed. This is the procedure described in the book, Dr. Bernstein's Diabetes Solution.