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Overview: Natalizumab is used to treat Crohn’s disease or relapsing forms of multiple sclerosis. Common side effects include diarrhea, headache, and nausea. Call your health care provider right away if you have a fever, unusual bleeding or bruising, or seizures. Natalizumab is given as an infusion into your vein (IV) by your health care provider.

Uses

What is natalizumab used for?

Natalizumab is used to treat relapsing forms of multiple sclerosis and Crohn’s disease.

Natalizumab may also be used for other conditions as determined by your health care provider.

How does natalizumab work (mechanism of action)?

Natalizumab is a type of medicine called an integrin receptor antagonist. It works on the immune system to prevent the movement of certain cells to different parts of your body. This helps reduce damage and inflammation, such as in the central nervous system (CNS) or in your gut.

How is natalizumab supplied (dosage forms)?

Brands and other names

  • Tysabri
  • Tyruko

Dosage forms and strengths

  • Natalizumab is available in an injectable form that is given by a health care provider.

How should I store natalizumab?

Natalizumab is usually given by a health care provider in a hospital or clinic. You will not store it at home.

Side Effects

What are the most common side effects of natalizumab?

The most common side effects of natalizumab are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Headache
  • Feeling tired
  • Depression
  • Rash
  • Pain, such around the stomach, or in the arms and legs or joints
  • Diarrhea
  • Nausea
  • Infections, such as in the lungs, nose, throat, urinary tract, or vagina

There may be other side effects of natalizumab that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of natalizumab?

While less common, the most serious side effects of natalizumab are described below, along with what to do if they happen.

Severe Allergic Reactions. Natalizumab may cause allergic reactions, which can be serious. Stop using natalizumab and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Infections. Natalizumab can increase your risk of infections, including serious infections that may be life-threatening like meningitis or encephalitis. Call your health care provider right away if you have an infection or any of the following symptoms.

  • Burning or stinging when you pee
  • Cough or coughing up blood
  • Fever, sweats, chills, or muscle aches
  • Shortness of breath
  • Diarrhea or stomach pain
  • Weight loss
  • Severe headache
  • Confusion
  • Eye pain, redness, or vision changes

Progressive Multifocal Leukoencephalopathy (PML). People using natalizumab may develop a rare brain disease called PML. It is caused by a virus called the JC virus. PML is very serious and can lead to death. Call your health care provider right away if you have any of the following symptoms of PML while using natalizumab and for six months after you stop using this medicine.

  • Clumsiness or loss of coordination
  • Difficulty walking or speaking
  • Facial drooping
  • Vision problems
  • Thinking, memory, or personality changes
  • Weakness on one side of your body that gets worse
  • Seizures

Liver Damage. Liver damage, also called hepatotoxicity, can happen when using natalizumab. Call your health care provider right away if you have any of the following symptoms of liver damage.

  • Nausea or vomiting
  • Stomach or belly pain
  • Fever
  • Weakness or unusual tiredness
  • Itching
  • Loss of appetite
  • Light-colored poop
  • Dark-colored urine (pee)
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Severely Low Platelet Levels. Natalizumab can cause you to have a severely low number of platelets in your blood, also called thrombocytopenia. Platelets help to form blood clots. Having a low level of platelets may increase your risk of bleeding. Tell your health care provider if you have any of the following symptoms of low platelet levels.

  • Easy bruising or bleeding
  • Bleeding that does not stop
  • Nosebleeds
  • Purplish spots (purpura) on the skin or in the mouth due to bleeding under the skin

Warnings & Precautions

Who should not use natalizumab?

Allergies to Ingredients. People who are allergic to any of the following should not use natalizumab.

  • Tysabri
  • Tyruko
  • natalizumab
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in natalizumab.

Progressive Multifocal Leukoencephalopathy (PML). Natalizumab should not be used if you have or had PML. Your health care provider may perform certain tests before giving you natalizumab.

What should I know about natalizumab before using it?

Natalizumab is usually given by a health care provider in a clinic or hospital.

Natalizumab is only available through restricted distribution programs. It is important that you keep all of your appointments, including labs or other testing, while using natalizumab.

What should I tell my health care provider before using natalizumab?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if natalizumab is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Cancer, including leukemia or lymphoma
  • HIV or AIDS
  • Organ transplant
  • Weak immune system
  • Previous treatment with natalizumab
  • Fever or infection, including shingles or other long-lasting infection

Other Medicines and Supplements. Natalizumab may interact with other medicines and supplements. Before using natalizumab, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how natalizumab could affect pregnancy or harm a fetus. However, using natalizumab during pregnancy could cause low platelets or low red blood cells (anemia) in a newborn. Tell your health care provider right away if you are pregnant or plan to become pregnant.

Breastfeeding. Natalizumab passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should use natalizumab while breastfeeding.

Interactions

Does natalizumab interact with foods or drinks?

There are no known interactions between natalizumab and foods or drinks.

 It is unknown if drinking alcohol will affect natalizumab.

Does natalizumab interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. 

In particular, make sure that you discuss if you are using any of the following before using natalizumab.

  • Azathioprine (Azasan, Imuran), cyclosporine (Gengraf, Neoral, Sandimmune, and others), or mycophenolate (Cellcept), which are medicines that suppresses your immune system
  • Mercaptopurine (Purinethol, Purixan), which is a medicine used to treat a type of blood cancer
  • Mitoxantrone, which is a medicine used to treat certain types of multiple sclerosis and cancer
  • Methotrexate (Trexall and others), which is a medicine commonly used for rheumatoid arthritis or certain types of cancer
  • A tumor necrosis factor (TNF) blocker, such as such as adalimumab (Humira), certolizumab (Cimzia), etanercept (Enbrel), golimumab (Simponi), or infliximab (Remicade), which is a medicine that is used for certain types of arthritis and other conditions
  • A corticosteroid, such as dexamethasone, methylprednisolone, or prednisone, which is a medicine for certain inflammatory conditions

This may not be a complete list of medicines that can interact with natalizumab. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much natalizumab?

If you or someone else has used too much natalizumab, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of natalizumab?

Natalizumab is usually given by a health care provider in a clinic or hospital. Your health care provider will make sure you are receiving natalizumab as scheduled. 

If you miss an appointment to get your natalizumab dose, call to make another appointment as soon as possible.