Generic name: insulin aspart
Dosage form: Pen, Multidose vial, PenFill cartridge, FlexTouch pen
Drug class: Insulin

Medically reviewed by Melisa Puckey, BPharm. Last updated on Jul 25, 2024.

What is Fiasp?

Fiasp (insulin aspart) is a fast-acting insulin used to lower blood sugar (glucose) levels in patients with type 1 and type 2 diabetes, who require insulin for treatment. Fiasp reaches the bloodstream 2.5 minutes after injection and reaches its peak level in about 1 hour. Fiasp can be given at the start of a meal or within 20 minutes of starting to eat.

Fiasp is sometimes used together with a long-acting or intermediate-acting insulin.

Fiasp is available as: 

• Fiasp FlexTouch pen 3 ml (single-patient-use)
• Fiasp Multiple-dose vial 10 ml
• Fiasp  PenFill cartridge 3 ml
• Fiasp PumpCart cartridge 1.6ml

Fiasp became an FDA-approved medicine on September 29, 2017, for the company Novo Nordisk.

Fiasp side effects

Get emergency medical help if you have signs of insulin allergy: redness or swelling where an injection was given, itchy skin rash over the entire body, trouble breathing, fast heartbeats, feeling like you might pass out, or swelling in your tongue or throat.

Fiasp may cause serious side effects. Call your doctor at once if you have:

• heart problems--swelling, rapid weight gain, feeling short of breath; or
• low potassium - leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling.

Common side effects of Fiasp may include:

• low blood sugar;
• weight gain;
• low potassium;
• swelling in your hands and feet;
• skin rash, itching, redness, or swelling; or
• thickening or hollowing of the skin where you injected the medicine.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Related/similar drugs

Warnings

Never share an injection pen, cartridge, or syringe with another person, even if the needle has been changed.

Before taking this medicine

You should not use Fiasp if you are allergic to it, or if you are having an episode of hypoglycemia (low blood sugar).

Tell your doctor if you have ever had:

• liver or kidney disease; or
• low levels of potassium in your blood (hypokalemia).

Tell your doctor if you also take pioglitazone or rosiglitazone (sometimes contained in combinations with glimepiride or metformin). Taking certain oral diabetes medicines while you are using insulin may increase your risk of serious heart problems.

Tell your doctor if you are pregnant or breastfeeding.

Follow your doctor's instructions about using insulin if you are pregnant or you become pregnant. Controlling diabetes is very important during pregnancy, and having high blood sugar may cause complications in both the mother and the baby.

How should I use Fiasp?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Fiasp is injected under the skin, or as an infusion into a vein. A healthcare provider will give your first dose and may teach you how to properly use the medication by yourself.

Your healthcare provider will show you where on your body to inject Fiasp. Use a different place each time you give an injection. Do not inject into the same place two times in a row.

Do not inject Fiasp into skin that is damaged, tender, bruised, pitted, thickened, scaly, or has a scar or hard lump.

Fiasp should be given at the start of a meal or within 20 minutes after starting a meal.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you do not understand these instructions.

Prepare an injection only when you are ready to give it. This medicine should be clear and colorless. Do not use the medicine if it has changed colors or has particles in it. Call your pharmacist for new medicine.

If you use an injection pen, use only the pen provided with your medicine. If you use this medicine with an insulin pump, do not mix or dilute Fiasp with any other insulin. Change the medicine in the reservoir at least every 6 days.

Never share an injection pen, cartridge, or syringe with another person, even if the needle has been changed. Sharing these devices can allow infections or disease to pass from one person to another.

You may have low blood sugar (hypoglycemia) and feel very hungry, dizzy, irritable, confused, anxious, or shaky. To quickly treat hypoglycemia, eat or drink a fast-acting source of sugar (fruit juice, hard candy, crackers, raisins, or non-diet soda).

Your doctor may prescribe a glucagon injection kit in case you have severe hypoglycemia. Be sure your family or close friends know how to give you this injection in an emergency.

Also watch for signs of high blood sugar (hyperglycemia) such as increased thirst or urination.

Blood sugar levels can be affected by stress, illness, surgery, exercise, alcohol use, or skipping meals. Ask your doctor before changing your dose or medication schedule.

Fiasp is only part of a treatment program that may also include diet, exercise, weight control, blood sugar testing, and special medical care. Follow your doctor's instructions very closely.

Use a needle and syringe only once and then place them in a puncture-proof "sharps" container. Follow state or local laws about how to dispose of this container. Keep it out of the reach of children and pets.

In case of emergency, wear or carry medical identification to let others know you have diabetes.

What happens if I miss a dose?

Since Fiasp is used before meals, you may not be on a timed dosing schedule. Whenever you use Fiasp, be sure to eat a meal within 5 to 10 minutes. Do not use extra this medicine to make up a missed dose.

Keep insulin on hand at all times. Get your prescription refilled before you run out of medicine completely.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. Insulin overdose can cause life-threatening hypoglycemia. Symptoms include drowsiness, confusion, blurred vision, numbness or tingling in your mouth, trouble speaking, muscle weakness, clumsy or jerky movements, seizure (convulsions), or loss of consciousness.

What should I avoid while using Fiasp?

Insulin can cause low blood sugar. Avoid driving or operating machinery until you know how Fiasp will affect you.

Avoid medication errors by always checking the medicine label before injecting your insulin.

Avoid drinking alcohol or using medicines that contain alcohol. Alcohol can cause low blood sugar and may interfere with your diabetes treatment.

What other drugs will affect Fiasp?

Insulin may not work as well when you use other medicines at the same time. Some drugs can also cause you to have fewer symptoms of hypoglycemia, making it harder to tell when your blood sugar is low. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here. Tell your doctor about all medicines you start or stop using.

Keep this medicine in its original container protected from heat and light. Do not draw insulin from a vial into a syringe until you are ready to give an injection. Do not freeze insulin or store it near the cooling element in a refrigerator. Throw away any insulin that has been frozen.

Fiasp Storage

 Storage Conditions for Vial, FIASP FlexTouch, PenFill Cartridges and PumpCart Cartridges

*Pump Reservoir: The total in use time is 28 days, including 6 days in the pump reservoir

**PumpCart Cartridges: The maximum time at room temperature is 18 days including 4 days in the pump

Unused vials should be stored between 2° to 8°C (36° to 46°F) in a refrigerator, but not in or near a freezing compartment. Insulin should not be exposed to excessive heat or light and must never be frozen. Do not use this medicine if it has been frozen. Insulin should not be drawn into a syringe and stored for later use.

Keep the cap on the pen in order to protect from light. Remove the needle from the FlexTouch pen after each injection and store without a needle attached. Use a new needle for each injection. Keep unused vials, FlexTouch, PenFill Cartridges and PumpCart cartridges in the carton so they will stay clean and protected from light.

Fiasp and Medicare

Because of the prescription drug law, known as the Inflation Reduction Act, Medicare is able to negotiate directly with drug companies to improve access to some of the costliest single-source brand-name Medicare Part B and Part D drugs.

Fiasp is one of 10 drugs covered under Medicare Part D that were selected in 2024 for the first cycle of negotiation based on Total Expenditures under Part D and other criteria as required by the law. Negotiations with participating drug companies are ongoing, and any negotiated prices for the first cycle of negotiation is effective from 2026.

Company

Fiasp Manufactured by: Novo Nordisk Inc., 800 Scudders Mill Road, Plainsboro, New Jersey 08536

Fiasp Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for Fiasp.

biosimilar products

Biosimilar products can only be dispensed in place of the reference product if the healthcare provider specifically prescribes the biosimilar product by name.

Pharmacy laws for biosimilar prescribing may vary by state

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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