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Natalizumab Side Effects

In Summary

Commonly reported side effects of natalizumab include: fatigue and antibody development. Other side effects include: dysmenorrhea, gastroenteritis, hypersensitivity reaction, and irregular menses. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to natalizumab: intravenous solution

As well as its needed effects, natalizumab may cause unwanted side effects that require medical attention.

If any of the following side effects occur while taking natalizumab, check with your doctor or nurse immediately:

More common:
  • Body produces substance that can bind to drug making it less effective or cause side effects
  • cough
  • difficulty with swallowing
  • dizziness
  • fast heartbeat
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • shortness of breath
  • skin rash, hives, or itching
  • tightness in the chest
  • unusual tiredness or weakness
  • Abdominal or stomach fullness
  • blurred vision
  • changes in behavior
  • chest pain
  • confusion
  • difficult or labored breathing
  • faintness or lightheadedness when getting up suddenly from a lying or sitting position
  • feeling of warmth
  • feeling unusually cold
  • fever
  • gaseous abdominal or stomach pain
  • nausea
  • redness of the face, neck, arms, and occasionally, upper chest
  • shivering
  • sneezing
  • sore throat
  • sweating
  • thoughts of killing oneself
  • yellow eyes or skin
Incidence not known:
  • Back pain
  • convulsions
  • drowsiness
  • headache

Minor Side Effects

Some natalizumab side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

More common:
  • Bladder pain
  • blistering, crusting, irritation, itching, or reddening of the skin
  • bloody or cloudy urine
  • cracked, dry, scaly skin
  • diarrhea
  • difficult, burning, or painful urination
  • difficulty with moving
  • discouragement
  • feeling sad or empty
  • frequent, strong, or increased urge to urinate
  • irregular menstruation
  • irritability
  • itching of the vagina or genital area
  • loss of appetite
  • loss of interest or pleasure
  • lower back or side pain
  • muscle pain or stiffness
  • pain during sexual intercourse
  • pain in the joints
  • pain, cramps, or heavy bleeding
  • passing urine more often
  • stomach pain
  • stomach soreness or discomfort
  • swelling
  • swollen glands
  • thick, white vaginal discharge with no odor or with a mild odor
  • trouble concentrating
  • trouble sleeping
Less common:
  • Absent, missed, or irregular menstrual periods
  • chest discomfort
  • fainting
  • local bleeding
  • shakiness in the legs, arms, hands, or feet
  • stopping of menstrual bleeding
  • trembling or shaking of the hands or feet

For Healthcare Professionals

Applies to natalizumab: intravenous concentrate

Nervous system

Very common (10% or more): Headache (up to 38%)
Common (1% to 10%): Vertigo, somnolence, tremor, dizziness
Uncommon (0.1% to 1%): Progressive multifocal leukoencephalopathy (PML)
Frequency not reported: Tremor[Ref]


Very common (10% or more): Upper respiratory tract infection (up to 22%), lower respiratory tract infection (up to 17%)
Common (1% to 10%): Pharyngolaryngeal pain, cough, sinusitis, nasopharyngitis[Ref]


Very common (10% or more): Depression (19%)[Ref]


Very common (10% or more): Nausea (up to 17%), gastroenteritis (up to 11%), abdominal discomfort (up to 11%), diarrhea (up to 10%)
Common (1% to 10%): Dyspepsia, constipation, flatulence, aphthous stomatitis
Frequency not reported: Vomiting[Ref]


Very common (10% or more): Influenza-like illness (up to 12%)
Common (1% to 10%): Herpes, tonsillitis, viral infection, immunogenicity[Ref]


Common (1% to 10%): Abnormal liver function test
Postmarketing reports: Serious liver injuries, increased liver enzymes, hyperbilirubinemia[Ref]


Very common (10% or more): Fatigue (up to 27%)
Common (1% to 10%): Tooth infections, toothache
Frequency not reported: Flushing, feeling cold, pyrexia[Ref]


Frequency not reported: Localized hypersensitivity reactions[Ref]


Very common (10% or more): Urinary tract infection (up to 21%), vaginitis (up to 10%)
Common (1% to 10%): Irregular menstruation, dysmenorrhea, amenorrhea, ovarian cyst, urinary incontinence, urinary urgency/frequency[Ref]


Very common (10% or more): Arthralgia (up to 19%), pain in extremity (up to 16%), back pain (up to 12%)
Common (1% to 10%): Rigors, muscle cramp, joint swelling[Ref]


Very common (10% or more): Rash (up to 12%)
Common (1% to 10%): Dermatitis, pruritus, night sweats, dry skin, urticaria[Ref]


Common (1% to 10%): Immediate or delayed hypersensitivity reactions, seasonal allergy
Frequency not reported: anaphylaxis/anaphylactoid reaction[Ref]


Rare (less than 0.1%): Anemia, hemolytic anemia[Ref]


Common (1% to 10%): Weight increased, weight decreased, peripheral edema[Ref]


Common (1% to 10%): Chest discomfort[Ref]


1. "Product Information. Tysabri (natalizumab)." Elan Pharmaceutical/Athena Neurosciences Inc, South San Francisco, CA.

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

3. Pharmaceutical Society of Australia "APPGuide online. Australian prescription products guide online. Available from: URL:" ([2006]):

It is possible that some side effects of natalizumab may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.