Managing the ups and downs of diabetes is no easy task. Some days, the pump is your best friend, giving you freedom and precise control. Other days, you come down with a rough case of “alarm fatigue” and just need a break—whether you’re hitting the beach, traveling, or simply want to go unplugged for a bit. That’s where knowing how to mix Multiple Daily Injections (MDI) into your pump routine comes in handy.
In this post, I’ll walk you through how to take a break from your pump, how to transition back, and how to mix things up by using MDI and your pump together. There’s lots of resources on this topic out there, so my goal is to keep it simple, practical, and give you everything you need to know, and nothing you don’t. Let’s dive in!
Disclaimer: Always consult with your healthcare professional before making any changes to your insulin doses or diabetes management routine. Individual needs vary, and proper guidance is essential for safe and effective diabetes care.
Why Go MDI?
Device/alarm fatigue is a very real thing, and while having a bionic pancreas strapped to your hip can be a huge help, sometimes, you just need to disconnect and go off the grid for a while. Other times, you’re forced to forgo your diabetes tech… maybe your pump malfunctions and your replacement is stuck in snail mail. Being prepared with a backup MDI routine is not only helpful, it could literally save your life! Whatever the reason, here’s how to prep for your tech vacation and make a successful transition back to MDI.
How to Transition to MDI
Basal Insulin (Your Long-Acting Insulin): One of the most important jobs of your insulin pump is to deliver little insulin “drips” under your skin throughout the day (otherwise known as your basal insulin). As soon as you disconnect your pump, that insulin drip stops. So it’s important to quickly start back on a long-acting insulin like Lantus, Basaglar, or Tresiba to avoid any dangerous hyperglycemia. You’ll want to talk to your healthcare provider to figure out the right dose—they’ll help calculate your current basal insulin needs based on your basal rates in your pump. Keep in mind, your blood sugars likely won’t be perfect when making this swap, so give yourself some grace and be patient if your glucose levels aren’t exactly where you want them on day 1.
Fun fact bubble: It’s not a 1-to-1 swap from pump basal to injection basal (for example, if you get 20u of basal on your pump, you likely won’t need exactly 20u of basal from your long-acting insulin). Insulin delivered through a pump is actually a bit more “efficient,” so many people need less basal on a pump compared to injections. For example, if someone needs 20u of daily basal on a pump, they may need 23-25u of daily long-acting insulin on MDI.
Bolus Insulin (Your Mealtime/Correction Insulin): Because you won’t be able to deliver a meal bolus from your pump, you’ll also need to figure out a strategy for getting those all-too-important meal doses and corrections in. You have two options here:
Either way, you will want to be sure you reach for a rapid-acting insulin (like Humalog, Novolog, Fiasp, or Lispro) with the same carb ratio and correction factor that you use in your pump.
Stay on Top of It: Since MDI doesn’t have the automated features your pump does, you’ll need to be extra diligent with insulin injections and blood sugar checks. Set reminders on your phone or watch to check your blood sugar and give your doses, especially for basal doses if you’re not used to doing it manually.
When you’re ready to return to your pump, it’s a pretty simple process, but there’s one very important thing to remember. You must watch for overlap!
Let’s pretend your roommate Daniel just took a weeklong pump vacation, and he is ready to get back on his pump today. Daniel decides that after lunch he is going to start up his pump again, so he puts on a new infusion set, fills his cartridge, and is off to the races! Well, by dinnertime his blood sugar is DROPPING FAST, and it won’t come up no matter what he eats… What did Daniel forget about? Overlap.
Overlap refers to the long-acting insulin still working in your system when switching to a pump. Daniel took his long-acting insulin dose in the morning, which lasts for 24 hours, but his pump didn’t know this… So as soon as he put that pump back on, boom, he was getting DOUBLE the basal insulin, leading to severe lows. As you can see, this can be quite a dangerous thing to miss.
You can approach overlap in 2 ways:
Either way, you’re going to want to keep a closer watch on your blood sugar levels whenever you do start the pump in case there’s still some extra long-acting insulin “hanging around” in your body.
Why Use Both MDI and Your Pump?
There might be days when you don’t want to be completely detached from your pump but also don’t want to wear it 24/7. Maybe you’re spending a long day at the beach or pool, going for a run, or just want to be free of it for a few hours. Maybe you are having issues with your site, and you need to take a single injection to be sure you’re getting some insulin. It may seem complicated, but there are some simple ways you can mix and match your pump and MDI routine, giving you the best of both worlds.
Pump Basal + Injection Boluses
When to Try Partial MDI
Timing is Key: Make sure you keep a close watch on your BG’s and plan the timing of hooking back up to your pump. You don’t want it overlapping too much with the long-acting insulin when you plug back in. Again, you’ll want to give your long-acting insulin at least 24 hours before going back fully on the pump.
Injections During Site Issues
As mentioned above, there may be times where you are having issues with your site or your pump, and your blood sugars are through the roof. Whether it’s a technical issue with the pump or an issue with your infusion set, you aren’t sure if you’re even getting your insulin (meaning you likely don’t feel too great either). This is a time where adding an injection (or two) along with your pump is warranted.
Now, this one comes with some disclaimers. ALWAYS reach out to your healthcare provider if you feel unsure or unwell before making adjustments to your treatment. If you’re in a bind with no other options, you can always use your fast-acting pen or a syringe for corrections or even for your meal bolus while you’re waiting for the new site to take. Just remember not to double-dose! Your pump keeps track of insulin on board (IOB), but those syringes and pens don’t, so you may need to pull out a piece of paper or make a note on your phone of when and how much you took.
Whether you’re taking a break from your pump, mixing MDI with your pump, or just getting through a temporary malfunction, knowing how to manage your diabetes through a variety of insulin delivery methods is a great skill for your diabetes toolbox.