How to refill your Fiasp insulin pen

Written by Dr. Jamie Winn
Aug 29, 2023

Fiasp, a fast-acting insulin aspart injection, is a trademark of Novo Nordisk A/S. It is available in a multi-dose vial, a FlexTouch pen, a PenFill cartridge and device, and a PumpCart cartridge for use in compatible insulin pumps. These will come with separate instructions on how to properly use them. Your healthcare provider should demonstrate these instructions prior to you giving your first dose. Here will discuss how to use your Fiasp PenFill cartridge, how it works, its side effects, and other important frequently asked questions.

How to use your Fiasp PenFill cartridge

To prepare to give your injection of Fiasp:

Wash your hands using water and soap.
Check your Fiasp cartridge label and ensure that it is the right insulin. This is very important if you use multiple types of insulin.
If this is the first use, the tamper-resistant foil will be in place. If it is not there or is broken, do not use it.
Inspect the cartridge as well as the insulin in it. Do not use it if the cartridge is damaged, if the threaded end is loose, or if the insulin is cloudy or colored.

To give your Fiasp injection:

Insert a Fiasp cartridge threaded end first into a compatible device.
Tear the paper tab off of a new needle and attach it to the delivery device only when you are going to give the injection. Be sure the needle is not bent or damaged and that is screwed on tight. Do not reuse needles or share them with other people.
Pull the outer cap off of the needle but don’t throw it in the trash. Then pull the inner cap off of the needle and discard it.
You will then need to be sure there are not any air bubbles blocking the insulin flow. You will do an air shot prior to each injection to prevent injecting yourself with air. This will also ensure you get the full dose of medication. The instructions on how to do an air shot will vary and be specific to the device you are using. They should be found in the instruction manual that comes with the device.
You should test your cartridge up to 6 times until you see a drop of insulin at the tip of the needle. If you don’t see an insulin drop after 6 times, you need to change the needle and repeat this step.
The dose counter should be at 0 before selecting your dose. You will turn the selector clockwise until the pointer lines up with your correct dose. Your pen will click with each unit of insulin you dial up.
It is now time to inject your dose of Fiasp. Inject this medication exactly as instructed to you by your doctor or healthcare provider. They will tell you if you need to pinch your skin before giving an injection. You should inject Fiasp at the beginning of a meal or within 20 minutes after you start eating. You can inject Fiasp subcutaneously (under the skin) of your abdomen (stomach), upper arms, or thighs. Clean the injection site with an alcohol swab after each injection, let it dry, and do not touch it.
Rotate your injection sites with each dose. Do not give an injection into skin that has pits, lumps, or is thickened. Also avoid skin that is damaged, bruised, tender, hard, or has scars.

Fiasp FAQs

What is Fiasp used for?

Fiasp (insulin aspart) is a rapid-acting insulin that is given as a subcutaneous injection. It is FDA-approved to improve blood sugar control in adult and pediatric patients with:

Type 1 diabetes mellitus (T1DM)
Type 2 diabetes mellitus (T2DM)

How does Fiasp work?

Fiasp (insulin aspart) is a fast-acting insulin that works like the hormone your pancreas makes. It causes your body to absorb and store sugar from your bloodstream and stop your liver from making more glucose. Fiasp is typically given as a mealtime insulin dose to help prevent hyperglycemia (high blood sugar levels) after eating.

Fiasp is unique from other aspart products and fast-acting insulins such as glulisine and lispro because it has L-arginine and niacinamide in it to help you absorb the medication quicker.

What are the most common side effects of Fiasp?

The most common side effects of Fiasp include:

Hypoglycemia (low blood glucose levels)
Infusion and injection site reactions
Allergic reactions (rash over your whole body, difficulty breathing, fast heartbeat, swelling of your face, tongue, or throat, extreme drowsiness, dizziness, or confusion)
Cutaneous amyloidosis (skin with lumps)
Lipodystrophy (buildup of body fat)
Weight gain

Fiasp can rarely cause serious side effects such as:

Dangerously low blood sugars
Hypokalemia (low potassium levels)
Increased risk of disease and infections if you share your pen, syringe, or needle with anyone else
Swelling and worsening heart failure if taken along with a thiazolidinedione like Actos (pioglitazone)

Disclaimer: These are not all of the possible side effects of Fiasp. You should always seek medical advice from your healthcare professional for any questions or concerns about your medical condition or treatment. You should also read all of the important safety information, prescribing information, and instructions for use that come with this medication. You can report side effects to FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Are there any drug interactions with Fiasp?

When Fiasp is taken along with other drugs, it can change how Fiasp works or make some side effects more likely or severe. You should ask your healthcare provider if any of the prescription drugs, over-the-counter (OTC) drugs, supplements, or vitamins you take may interact with Fiasp to be sure there are no contraindications or need for dose adjustments. Some drug interactions with Fiasp include:

Antidiabetic medications such as long-acting insulin products or meds that affect your blood sugar such as glucagon
Meds that block signs and symptoms of low blood sugar such as beta-blockers, guanethidine, clonidine, and reserpine

What should you tell your doctor before starting Fiasp?

Before starting Fiasp, be sure your healthcare provider is aware of all your medical conditions, including:

Kidney problems
Liver problems
Are pregnant or plan on becoming pregnant
Are breastfeeding or plan to breastfeed as it is not known if this medication is found in the breast milk

What warnings are there with Fiasp?

You should never share your pen, syringe, cartridge, or cartridge device to avoid infections and disease.

Serious life-threatening low blood sugars can occur with Fiasp. Increase your blood glucose monitoring with any changes in your insulin dose, diet, physical activity, or diabetes medications.

Fiasp has been associated with a possible risk of low potassium levels. You should be monitored if you are at risk of hypokalemia and treated if necessary.

Fluid retention and heart failure, when used with thiazolidinediones (TZDs), have been reported. Monitor and consider a dose reduction or discontinuation if heart failure occurs.

If you drink alcohol with Fiasp, your need for insulin may change as your blood sugar level may either rise or fall.

What type of insulin is Fiasp?

Fiasp is a fast-acting insulin aspart that is used to manage blood sugars in type 1 and type 2 patients. It is different from other insulin aspart formulations because it contains L-arginine and niacinamide which help you absorb Fiasp more rapidly.

Can you use Fiasp in an insulin pump?

An insulin infusion pump is a small computerized device with a display screen, a reservoir to hold insulin, and an infusion set that attaches to your body. Not all insulins are safe to use in an insulin pump.

Insulin pumps typically use faster-acting insulins such as Fiasp (insulin aspart), Humalog (insulin lispro), and Apidra (insulin glulisine). Because the pump delivers small amounts of insulin every few minutes, longer-acting insulins are not necessary.

How should you store Fiasp?

Store your unused Fiasp FlexTouch Pens or vials in the refrigerator between 36°F to 46°F (2°C to 8°C) or at room temperature below 86°F (30°C). Once it has been opened, store it at room temperature below 86°F (30°C) or in the refrigerator between 36°F to 46°F (2°C to 8°C) for up to 28 days.

Store your unused Fiasp PenFill cartridges in the refrigerator between 36°F to 46°F (2°C to 8°C). After you begin using it, store it in the delivery device at room temperature below 86°F (30°C) for up to 28 days. Do not put it back in the refrigerator.