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NovoLog® FlexPen®

NovoLog® (NŌ-vō-log) FlexPen® allows you to give your child insulin without having to get medicine out of a vial with a separate syringe.

The NovoLog FlexPen contains insulin aspart (AS-part), also called NovoLog, which is a rapid-acting insulin.

  • It is used to help patients with high blood sugar levels.
  • It is a clear, colorless liquid that is injected under the skin.
  • NovoLog starts acting very fast.
  • It may be prescribed by your doctor to take before meals or as a correction dose for a high blood sugar level.

The NovoLog FlexPen can be taken almost anywhere. You can fit it in your pocket or purse.

The NovoLog FlexPen

NovoLog FlexPen is a prefilled disposable device that looks like a pen. It contains 300 units of U-100 NovoLog insulin.

NovoLog FlexPen can deliver doses from 1 to 60 units in a single injection. The large dose display shows the number of units you have selected to give as a single dose.

Novolog FlexPen

The NovoLog FlexPen looks like a pen. It provides a convenient way to give insulin.

Needles for the NovoLog FlexPen

You will receive needles made specifically for the NovoLog FlexPen. These are called NovoFine® needles.

Novolog FlexPen

Use only a NovoFine needle in the NovoLog FlexPen.

  • Common types of pen needles include standard pen needles and safety pen needles.
  • Standard pen needles have an outer cover and a removable inner needle cover. You remove both before the injection.
  • Safety pen needles have an outer cover that you remove and a fixed inner needle shield that you do not remove before the injection. This is meant to protect anyone handling the needle after the injection. It is commonly used in the hospital. If you were trained to give the injection with a safety needle, ask the doctor or nurse to train you on the proper use of the standard needles.
Standard pen needle
Safety pen needle

The NovoLog FlexPen uses either a standard needle or a safety needle. Use the type that you were trained to use.

  • With each new box of pen needles, check to see if they are the same type you were trained to use. If you are unsure, ask the doctor or nurse to show you how to use the needles.
  • Always use a new needle for each injection.
  • Throw the needle away right after you give the injection.
  • Do not store your child’s NovoLog FlexPen with a needle attached.
  • The medicine in your NovoLog FlexPen should be given using this device. Do not attempt to remove the medicine from the NovoLog FlexPen or transfer it from one NovoLog FlexPen to another.

How to store the NovoLog FlexPen

  • Keep the NovoLog FlexPen you are currently using out of the refrigerator and at a temperature below 86°F.
  • Store any unused NovoLog FlexPens in your refrigerator.
  • Do not freeze a NovoLog FlexPen. Do not use the device if the NovoLog in it has been frozen.
  • Keep NovoLog FlexPen away from heat or light.
  • The NovoLog FlexPen you are currently using should be thrown away 28 days after the first time it was used, even if it still has insulin left in it.
  • An unused NovoLog FlexPen may be used until the expiration date printed on the label, if kept in the refrigerator.

Injection sites

NovoLog FlexPen is used to give an injection (shot) of NovoLog under the skin. This injection is given into the fatty areas of the body called injection sites.

The usual sites are:

  • Stomach (abdomen)
  • Upper thighs
  • Back of upper arms

Rotate the injection sites each time so that the fat areas do not get irritated and scarred. Do not use the same site for each injection. Never inject NovoLog into a vein or muscle.

Getting ready

  • Wash your hands with soap and water. Dry them well. Or, use an alcohol-based hand sanitizer.
  • Check the NovoLog FlexPen label to make sure you are giving the right type of insulin. This is especially important if your child takes more than 1 type of insulin.
  • Do not use the NovoLog FlexPen past the expiration date printed on the label or 28 days after the first time you used the NovoLog FlexPen.
  • Always use a new needle for each injection to help ensure it is germ-free and to prevent clogged needles.
  • Gather the following supplies:
    • NovoLog FlexPen
    • A new NovoFine needle
    • Alcohol swabs
    • Sharps container

Preparing the NovoLog FlexPen

  • Pull the pen cap straight off.
  • Check the liquid in the NovoLog FlexPen pen. Levemir should look clear and colorless. Do not use it if it looks cloudy or colored.
  • Wipe the rubber stopper with an alcohol swab.
  • Select a new needle. Pull off the paper tab from the outer needle cap.
  • Push the capped needle straight onto the FlexPen and twist the needle until it is tight.
  • Pull off the outer needle cap.
  • Pull off the inner needle cap if it can be removed and throw it away.
Pulling off the outer and inner needle caps

Pull off the outer needle cap and the inner cap if it can be removed.

Air shots

You should do an air shot before each injection, after the needle is attached.

Performing an air shot helps you check that the insulin flow is good before you select and inject the dose. This way you can make sure that your child receives the full dose and avoid injecting air.

To do an air shot:

  • Turn the dose selector to 2 units.
Turning the dose selector

Turn the dose selector to show the required number of units.

  • Hold the FlexPen with the needle pointing up. Tap the top of the FlexPen gently a few times to let any air bubbles rise to the top.
  • While still holding the FlexPen with the needle pointing up, press and hold the dose button until the dose counter shows “0.” The “0” must line up with the dose pointer.
  • A drop of insulin should be seen at the needle tip.
    • If you do not see a drop of insulin, repeat the air shot instructions. Do this no more than 6 times.
    • If you still do not see a drop of insulin after 6 attempts, do not use the NovoLog FlexPen and contact the doctor.

Selecting your child’s dose

Turn the dose selector to select the number of units you need to inject. The dose pointer should line up with your child’s dose.

  • If you select the wrong dose, you can turn the dose selector forward or backward to correct the dose.
  • When turning the dose selector, be careful not to press the push-button because insulin will come out.
  • The even numbers are printed on the dial.
  • The odd numbers are shown as lines.

Giving the injection

  • Wipe the chosen injection site with an alcohol swab for 30 seconds.
  • Let area dry for 30 seconds. Do not blow on, blot, or wipe area.
  • Wrap your fingers around the FlexPen with your thumb above the push-button. Do not press the push-button before inserting the needle into your child's skin.
  • Insert the needle into your child's skin.
  • Press and hold down the push-button until the counter shows “0.” The “0” must line up with the dose pointer.
Giving the injection

Press and hold down the push-button until the counter shows “0.”

  • Keep the needle in your child’s skin after the dose counter has returned to “0” and slowly count to 6.
    • When the dose counter returns to “0”, your child will not get the full dose until 6 seconds later.
    • If the needle is removed before you count to 6, you may see a stream of insulin coming from the needle tip and your child will not get the full dose.
    • If this happens, you should check your child’s blood sugar level more often because more insulin may be needed.
  • Pull the needle out of your child’s skin.
    • If you see blood after you take the needle out of the skin, press the injection site lightly with a piece of gauze or an alcohol swab. Do not rub the area.
  • Carefully remove the needle from the Novolog FlexPen, and throw the needle away in a sharps container.
  • Do not recap the needle.
  • Replace the pen cap by pushing it straight on.

Possible side effects

Early side effects may include:

  • Itching or rash at the injection site.
  • Skin thickening or pits at the injection site 
  • Allergic reactions

Later side effects may include:

  • Low blood sugar (hypoglycemia)
  • Skin rash, itching
  • Weight gain

These are the most common side effects, but there may be others. Please report all side effects to the doctor or nurse.

In case of a severe side effect or reaction, call your doctor, nurse, or pharmacist at 901-595-3300. If you are outside the Memphis area, dial toll-free 1-866-278-5833, and press 0 once the call is connected.

Special instructions      

  • Know the type and strength of your child’s insulin. Do not change your child’s insulin type unless the doctor tells you to do so.
  • Do not share needles, insulin pens, or syringes.
  • Check your needles to make sure they are the same needles you were trained to use. If they are not, ask the doctor or nurse to show you how to properly use your needles.
  • While your child is taking NovoLog, tell the doctor right away if your child has any of these symptoms:
    • Trouble breathing
    • Shortness of breath
    • Fast heartbeat
    • Swelling of the face, tongue, or throat
    • Sweating
    • Feeling very drowsy
    • Feeling dizzy or confused

Low blood sugar

Know the signs of low blood sugar. Young children may not understand the signs of low blood sugar.

Common signs of low blood sugar are:

  • Anxiety
  • Confusion
  • Feeling irritable
  • Headache
  • Mood changes
  • Shaking
  • Feeling dizzy
  • Fast heartbeat
  • Sweating
  • Feeling tired

If your child has any of these signs, check the blood sugar right away.

If the blood sugar is less than 70 mg/dL, give your child a quick source of sugar. Always carry some type of quick sugar source with you.

Check your child’s blood sugar 15 minutes after treating the low blood sugar. If the blood sugar is less than 70mg/dL the second time, treat again and call your child’s doctor. Once the blood sugar is above 70mg/dL, your child needs to eat a snack containing protein.

Quick sources of sugar to treat low blood sugar include:

  • Glucose tablets
  • Juice
  • Regular soda (not sugar-free)
  • Raisins
  • Saltine crackers
  • Sugar or corn syrup
  • Cake frosting

Do not use chocolate, cookies or cake to treat low blood sugar. These foods have lots of sugar but are high in fat, which makes them slower at boosting your child’s blood sugar.

Contact the doctor right away or go to the hospital in these cases:

  • Low blood sugar happens again
  • You cannot fix the low blood sugar
  • Your child has a seizure
  • Your child passes out
  • Your child is not feeling better in 2–3 days or is feeling worse

Learn how to check your blood sugar


If you have questions or concerns, please call 901-595-3300 and ask for your child’s primary clinic. If you are calling after hours or on the weekend, ask for the nursing coordinator. If you are outside the Memphis area, dial toll-free 1-866-278-5833.

Reviewed: August 2022