The Deadly Mix-Up: Why Checking Your Insulin Pen Labels Saves Lives

Lynn Johnston
Jan 4
3 min read

Double-Check, Every Time: Why "The Right Medication" is a Lifesaver

In the fast-paced world of a medication aide, your routine is your strongest tool—but it can also be your greatest enemy. When you’ve administered hundreds of doses throughout a shift, it’s easy to let muscle memory take over. However, in our profession, "autopilot" is where errors happen.

This week, we are focusing on one of the Six Rights of Medication Administration: The Right Medication. Specifically, we are looking at a common culprit in medication administration errors: Insulin Pens and Insulin Pen Safety.

The Visual Trap: Why Insulin Pens are Risky

If you look at a medication cart, you’ll notice that many insulin pens share the same shape, size, and branding. Manufacturers often use similar packaging for an entire line of products. To the naked eye during a busy med pass, a pen of Novolog can look dangerously similar to a pen of Tresiba.

This is known as "Look-Alike, Sound-Alike" (LASA) packaging. While companies use different colors to help distinguish them, colors should only be your second clue. Your first and most important clue must always be the printed name on the label.

Understanding the Duo: Short-Acting vs. Long-Acting

To understand why a mix-up is so dangerous, we have to look at how these medications work in the resident's body. Most residents on insulin use a "basal-bolus" routine, which involves two very different types of insulin:

Long-Acting Insulin (Basal): This is designed to work slowly over 24 hours. It provides a steady "background" level of insulin. Common examples include Lantus (Glargine) or Levemir.
Short-Acting/Rapid-Acting Insulin (Bolus): This is designed to work quickly, usually administered right before a meal to handle the spike in blood sugar from food. Common examples include Humalog (Lispro) or Novolog (Aspart).

The Math of a Medication Mistake: A Real-World Example

Let’s look at the scenario that keeps many nurses and medication aides up at night. Imagine you have a resident who is prescribed 50 units of Lantus (Long-acting) at bedtime and 5 units of Novolog (Short-acting) before meals.

Scenario A: The Swap If you accidentally pick up the Novolog pen and administer 50 units instead of the Lantus, you have just given that resident a massive dose of rapid-acting medication.

The Result: Within 15 to 30 minutes, the resident’s blood sugar will plummet. This can lead to severe hypoglycemia, seizures, coma, or even death if not caught immediately.

Scenario B: The Reverse Swap If you give 50 units of Lantus when you were supposed to give a small dose of Novolog before a meal, the resident won't have enough "fast" insulin to cover their food, leading to high blood sugar (hyperglycemia) in the short term. More dangerously, they now have a massive "reservoir" of long-acting insulin in their system that will continue to drop their blood sugar for the next 24 hours, making them a constant risk for a delayed "crash."

How to Prevent the "Pen Mix-Up"

As an unlicensed medication aide, you are the final line of defense. Here is how you can ensure you always have the right medication:

Read the Label, Not the Color: Never rely on the "orange cap" or the "grey pen." Manufacturers change designs, and different brands use different color schemes. Always read the actual words printed on the pen.
The Three-Point Check: 1. Check the pen when you pull it from the drawer/fridge. 2. Check the pen against the MAR (Medication Administration Record). 3. Check the pen one last time right before you dial the dose and the resident is in front of you.
Check the Concentration: Most insulin is U-100, but some pens are U-300 or U-500. Giving the wrong concentration is just as dangerous as giving the wrong type.
Separate the Pens: If a resident has both types of insulin, try to keep them physically separated in the medication cart or storage area to prevent grabbing the wrong one in a hurry.

Your Role is Vital

It might feel like a small thing to double-check a name you’ve seen a thousand times. But that five-second pause to read the word "Lantus" versus "Humalog" is exactly what stands between a routine evening and a medical emergency.

You are the eyes and ears of the clinical team. By being meticulous with your checks, you aren't just "passing meds"—you are actively saving lives.