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Tysabri Side Effects

Generic name: natalizumab

Medically reviewed by Philip Thornton, DipPharm. Last updated on Jun 25, 2022.

Note: This document contains side effect information about natalizumab. Some of the dosage forms listed on this page may not apply to the brand name Tysabri.

For the Consumer

Applies to natalizumab: intravenous solution


Intravenous route (Solution)

Progressive Multifocal LeukoencephalopathyNatalizumab increases the risk of progressive multifocal leukoencephalopathy (PML), an opportunistic viral infection of the brain that usually leads to death or severe disability.Risk factors for PML include the presence of anti-JC virus antibodies, duration of therapy, and prior use of immunosuppressants. These factors should be considered in the context of expected benefit when initiating and continuing treatment with natalizumab.Monitor patients, and withhold natalizumab immediately at the first sign or symptoms suggestive of PML.Because of the risk of PML, natalizumab is available only through a restricted distribution program called the TOUCH® Prescribing Program.

Side effects requiring immediate medical attention

Along with its needed effects, natalizumab (the active ingredient contained in Tysabri) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking natalizumab:

More common

  • Bladder pain
  • blistering, crusting, irritation, itching, or reddening of the skin
  • bloody or cloudy urine
  • body produces substance that can bind to drug making it less effective or cause side effects
  • chest tightness
  • cough
  • difficult, burning, or painful urination
  • difficulty with swallowing
  • dizziness
  • fast heartbeat
  • frequent, strong, or increased urge to urinate
  • hives, itching, skin rash
  • itching of the vagina or genital area
  • lower back or side pain
  • pain during sexual intercourse
  • passing urine more often
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • thick, white vaginal discharge with no odor or with a mild odor
  • unusual tiredness or weakness


  • Blurred vision
  • changes in behavior
  • chest pain
  • confusion
  • difficult or labored breathing
  • fainting 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
  • stomach fullness
  • sweating
  • thoughts of killing oneself
  • yellow eyes or skin

Incidence not known

  • Back, leg, or stomach pains
  • black, tarry stools
  • bleeding gums
  • chills
  • dark urine
  • drowsiness
  • general body swelling
  • headache
  • heavier menstrual periods
  • loss of appetite
  • nosebleeds
  • pale skin
  • pinpoint red spots on the skin
  • seizures
  • unusual bleeding or bruising
  • vomiting

Side effects not requiring immediate medical attention

Some side effects of natalizumab may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • Cracked, dry, scaly skin
  • diarrhea
  • difficulty with moving
  • discouragement
  • feeling sad or empty
  • irregular menstruation
  • irritability
  • loss of interest or pleasure
  • muscle pain or stiffness
  • pain, cramps, or heavy bleeding
  • pain in the joints
  • stomach soreness or discomfort
  • swollen glands
  • trouble concentrating
  • trouble sleeping

Less common

  • Absent, missed, or irregular menstrual periods
  • chest discomfort
  • 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


Frequency not reported: Acute retinal necrosis (ARN), blindness, decreased visual acuity, redness, eye pain[Ref]

Nervous system

Very common (10% or more): Headache (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 (22%), lower respiratory tract infection (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 (17%), gastroenteritis (11%), abdominal discomfort (11%), diarrhea (10%)

Common (1% to 10%): Dyspepsia, constipation, flatulence, aphthous stomatitis, tooth infection, tonsillitis

Frequency not reported: Vomiting[Ref]


Very common (10% or more): Influenza-like illness (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 (27%)

Common (1% to 10%): Tooth infections, toothache, rigors

Frequency not reported: Flushing, feeling cold, pyrexia[Ref]


Frequency not reported: Localized hypersensitivity reactions[Ref]


Very common (10% or more): Urinary tract infection (21%), vaginitis (10%)

Common (1% to 10%): Irregular menstruation, dysmenorrhea, amenorrhea, ovarian cyst, urinary incontinence, urinary urgency/frequency[Ref]


Very common (10% or more): Arthralgia (19%), pain in extremity (16%), back pain (12%)

Common (1% to 10%): Rigors, muscle cramp, joint swelling[Ref]


Very common (10% or more): Rash (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]

Frequently asked questions


1. "Product Information. Tysabri (natalizumab)." Elan Pharmaceutical/Athena Neurosciences Inc (2004):

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

3. Pharmaceutical Society of Australia "APPGuide online. Australian prescription products guide online." (2006):

Further information

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

Some side effects may not be reported. You may report them to the FDA.