Taking Koselugo

Taking koselugo

Kassidy, age 11, living with NF1 PN.
Kassidy is not a Koselugo patient

Are there any tests needed before starting Koselugo?

Select each of the following steps to help prepare for the next appointment with your child's doctor.

Find resources to help you and your child prepare for your doctor's visit.

Download the resources

Your child will take 3-4 tests before starting Koselugo:

  • A test using sound waves to painlessly create pictures of the heart (called an echocardiogram)
  • A blood test for certain enzymes and naturally occurring chemicals, including serum creatine phosphokinase (CPK) tests
  • An assessment of your child's eyes
  • A pregnancy test for females of reproductive potential

Find resources to help you and your child prepare for your doctor's visit.

Download the resources

How is Koselugo taken?

Koselugo has
a consistent,
dosing schedule

Koselugo is an oral medication taken twice daily, about 12 hours apart.

Koselugo can be taken on an empty stomach or with food.

Koselugo capsules must only be swallowed whole with water. They must not be chewed, dissolved, or opened. Taking Koselugo in a different way than instructed may affect how it works.

Tic Tac® Breath Mint


Koselugo Capsule

Similar in size to a Tic Tac®, Koselugo can be easy to take.

Images shown to scale.

  • If your child misses a dose, they should take it as soon as you remember. If it is less than 6 hours before the next scheduled dose, give the next dose at the regular time.
    Do not make up for the missed dose.

  • If your child vomits at any time after taking Koselugo, they should not take an additional dose. The next dose should be taken at the regular time.

Tic Tac® and the three-dimensional design are registered trademarks of Ferrero S.A.

To learn more or to contact your dedicated Case Manager, please visit www.alexiononesource.com/kos, or call
1-888-765-4747, Monday through Friday, 8:30 AM–8 PM ET.

Are there any tips for taking Koselugo?

Encouraging a child to take medicine can be a difficult task. Common reasons why children don’t want to take medicine may include:

  • Not understanding why they need to take it
  • Not liking the taste or texture
  • Having difficulty swallowing medication

It’s important that your child understands why it’s necessary to take 2 doses of Koselugo every day. Be sure to talk about it in a way that’s positive. And, as your child grows, you may want to change your approach to ensure that the dosing schedule is followed.

Suggestions to help give medicines to young children:

Role playing can be helpful: Pretending to give a favorite doll or teddy bear some medicine can make taking medicine more fun

Try to do a positive, fun activity after your child takes the medicine. This may help motivate your child to take the medicine again

For some helpful tips to teach your child how to swallow pills, you may want to download the brochure Medicine & Your Child: A Guide for Parents on Adherence and Administration or visit kidshealth.org to see Teaching Your Child How to Swallow Pills for additional suggestions.

Schedule your child's doses in a way that works best for you and your family

Parent kit

Parent Readiness Kit

Speak to your PEM to request the Parent Readiness Kit, which can provide you and your family with valuable resources and information such as Koselugo dosing, treatment, and available support. You can request a Parent Readiness Kit from your dedicated PEM by clicking below.

Request a kit
Actor portrayal

Actor portrayal

Educational Events

Attend an educational webinar to learn more about NF1 PN, Koselugo, and the support provided to families like yours by the Koselugo team.

View events


To receive the latest updates, tools, and tips about NF1 PN and Koselugo, please provide us with some information about yourself.

Please enter First Name

Please enter Last Name

Please enter Email

Please enter ZIP code


Please confirm

important safety information

What are the possible side effects of Koselugo?

Koselugo may cause serious side effects, including:

  • Heart problems. Koselugo can lower the amount of blood pumped by your heart, which is common and can also be severe. Your healthcare provider will do tests before and during treatment to check how well your heart is working. Tell your healthcare provider right away if you get any of the following signs or symptoms: persistent coughing or wheezing, shortness of breath, swelling of your ankles and feet, tiredness, increased heart rate.
  • Eye problems. Koselugo can cause eye problems that can lead to blindness. Your healthcare provider will check your vision before and during treatment. Tell your healthcare provider right away if you get any of the following signs or symptoms: blurred vision, loss of vision, dark spots in your vision (floaters), other changes to your vision.
  • Severe diarrhea. Diarrhea is common with Koselugo and can also be severe. Tell your healthcare provider right away the first time that you get diarrhea during treatment. Your healthcare provider may give you medicine to help control your diarrhea and may tell you to drink more fluids.
  • Skin rash. Skin rashes are common with Koselugo and can also be severe. Tell your healthcare provider if you get any of the following signs or symptoms: rash that covers a large area of your body, peeling skin, blisters.
  • Muscle problems (rhabdomyolysis). Muscle problems are common with Koselugo and can also be severe. Treatment with Koselugo may increase the level of a muscle enzyme in your blood called creatine phosphokinase (CPK) and may be a sign of muscle damage. Your healthcare provider should do a blood test to check your muscle enzyme levels of CPK before you start taking Koselugo and during treatment. Tell your healthcare provider right away if you get any of the following signs or symptoms: muscle aches or pain; muscle spasms and weakness; dark, reddish urine.

Before taking Koselugo, tell your healthcare provider about all your medical conditions, including if you:

  • have heart problems.
  • have eye problems.
  • have liver problems.
  • are pregnant or plan to become pregnant. Koselugo can harm your unborn baby. Your healthcare provider should verify if you/your partner are pregnant before beginning treatment. Ensure you/your partner use effective birth control (contraception) during treatment and for 1 week after your last dose if there is possibility pregnancy could occur. Tell your healthcare provider right away if you/your partner think you may be pregnant.
  • are breastfeeding or plan to breastfeed. It is not known if Koselugo passes into your breast milk. Do not breastfeed during treatment and for 1 week after your last dose. Talk to your healthcare provider about the best way to feed your baby during this time.

Tell your healthcare provider about all the medicines you take, including prescription, over-the-counter medicines, vitamins, or herbal supplements. Especially tell your healthcare provider if you are taking aspirin, blood thinners, or other medicines to treat blood clots. Koselugo contains vitamin E, which may increase risk of bleeding.

What should I avoid while taking Koselugo?

Do not drink grapefruit juice, eat grapefruit, or take supplements with grapefruit or St. John’s Wort during treatment.

Most common side effects include: vomiting, stomach-area pain, nausea, dry skin, muscle and bone pain, feeling of tiredness or lacking energy, fever, sores in your mouth, headache, redness around the fingernails, itching.

These are not all the possible side effects of Koselugo. Call your healthcare provider for medical advice about side effects. Your healthcare provider may change your dose, temporarily stop, or permanently ask you to stop taking Koselugo if you have any of these side effects. You may report side effects to AstraZeneca at 1-800-236-9933 or at https://
or FDA at
1-800-FDA-1088 or


What is Koselugo?

Koselugo is a prescription medicine that is used to treat children 2 years of age and older with neurofibromatosis type 1 (NF1) who have plexiform neurofibromas that cannot be completely removed by surgery. It is not known if Koselugo is safe and effective in children under 2 years of age.

All families shown in this website have been compensated by Alexion, unless otherwise noted.