Need help navigating life with diabetes? You can always Ask D’Mine!

Welcome again to  our weekly Q&A column, hosted by veteran type 1 and diabetes author Wil Dubois. This week, Wil’s addressing the consequences of using older, cheaper insulins in your insulin pump. 

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Evelynn, type 1 from Utah, writes:Well, I’m without insurance for a time. I’m a pumper and, because I have squirrel DNA, I have a healthy backlog of infusion sets and cartridges. The problem is I can’t afford to put insulin into said damn cartridges. Can I use the twenty-buck Walmart ReliOn insulin in the pump?

Wil@Ask D’Mine answers: Fans of Traders Joe’s famous Charles Shaw wines long ago nicknamed it “Two Buck Chuck.” Even though it’s now technically three-buck Chuck, the old name survives. I propose we D-folks should start calling ReliOn insulin Twenty-Buck Chuck.

Or maybe we need something better than “Chuck.” I’m open to suggestions. Email me.

Anyway, Walmart’s ReliOn brand is older, out of patent first-gen human insulin. The retail giant sells a basal “N,” a fast-acting “R,” and a mix. The private label originally launched with Novolin products, but in 2010 Walmart started filling their vials with Humulin from Lilly. 

This tidbit of history has a direct bearing on your question. 

Humulin, the first ever FDA approved recombinant DNA drug, received clearance waaaaay back in the fall of 1982. Another big milestone in diabetes happened the next year. The introduction of Al Mann’s MiniMed 502 insulin pump. While not the first pump—that honor goes to Dean Kamen’s AutoSyringe—the 502 was the first commercially successful one. And the first that was wildly popular with PWDs (people with diabetes), setting the stage for huge growth and innovation in the insulin pump ecosystem. Sadly, an ecosystem that, like the one the dinosaurs lived in, seems to have been struck by some sort of economic asteroid, leading to the extinction of many fine species.

But that’s a story for another day. My point in pointing out the near-common lineage of the insulin pump and old-style insulin is that insulin pumps were born to pump Twenty Buck Chuck. So, yes, fill ‘er up.

That said, of course, there are some things to be aware of. Modern pumps are optimized and programmed for modern insulins, which have different characteristics than older insulins when it comes to the shape of their action curve and their duration of action. In other words, this is not a plug-and-play solution, but with some care it’s fully doable.

The insulins you’re used to using start working in 15 minutes, peak in two hours, and effectively last for three-to-four hours in most adults. Good ol’ R is quite different. It takes fully half an hour to start working, peaks in three hours, and lasts six-to-eight hours in most adults.

So it’s slower to get on the job, works hardest later, and hangs around until the cows come home. That means that you should pre-bolus, if at all possible, so that the insulin has started to work when the carbs hit your blood stream. It also means you should re-set the duration of action on your pump’s dosing calculator.

I should also mention that R might pack a slightly bigger wallop than more modern formulations. While the highly respected Pharmacist’s Letter in 2009 suggested “unit-to-unit conversion” between the newer insulins and the older R, I stumbled upon this more recent document from the American Diabetes Association guiding emergency workers on how to handle insulin stitches during disaster responses. It says that when switching from modern insulins to the older ones, the dose should be lowered by 20%. That’s for shots. What does it say about pumps? Not much. The only guidance it gives on pumps is to say, “fer God’s sake don’t put basal insulin in a pump.”

OK. I might have paraphrased that.

Still, with that 20% in mind, it suggests to me that using the same amount of R that you currently use could routinely overdose you. In an abundance of caution, to start out with, I’d reduce the insulin-to-carb ratios and correction factors by 20%, along with each step of your basal program. Hey, it’s easier to crank it back up later if you’re running a bit high, than to deal with a hurricane of hypos.

Oh, and one other thing. Don’t get itchy fingers. This insulin is slow and long-acting. It won’t fix highs as quickly as you’re used to. If you get impatient and throw several corrections at a high, the R will stack up on you like a ton of bricks. Or maybe a better illustration would be the classic falling safe or piano from a Saturday morning cartoon.

Just be patient with it at first. 

Now, as to squirrel DNA, hey those squirrels ain’t dumb. You never know how long winter might last, and a cache of nuts to keep you going is always a great idea. In fact, that’s probably why we mammals rule the planet and the dinos died out: Our ancient squirrel ancestors stocked up on food and rode out the asteroid disaster. When I pumped, I routinely stretched sets an extra day to create a backlog of supplies. For just in case. I’m not saying that it should be your normal operating procedure. Insulin isn’t keen on being in plastic for too long, nor does your flesh like tubes jammed into in for extended periods of time—so stretching sites increases the risk of blood sugar control problems—but doing it every now and again is a good idea, if for nothing else than to protect you from shipping delays on supplies, which our health insurance companies make us wait until the last second for. (Hey, we might die at any minute and if they supplied us early, they’d be out all that beautiful money. And wouldn’t that be tragic?) 

Anyway, thanks for writing. I’m glad your squirrel DNA has you well set with acorns, infusion sets, and pump cartridges. And with a little care you’ll be fine with the Twenty-Buck Chuck, and hopefully you’ll have enough money left over for a bottle or two of Two-Buck Chuck to help ease your stress over your lost health insurance. 


This is not a medical advice column. We are PWDs freely and openly sharing the wisdom of our collected experiences — our been-there-done-that knowledge from the trenches. Bottom Line: You still need the guidance and care of a licensed medical professional.