Natalizumab
Natalizumab is a monoclonal antibody used to treat multiple sclerosis and Crohn's disease. It works by preventing immune cells from crossing into the brain and gut, reducing inflammation and slowing disease progression. This medication is typically prescribed when other treatments have not been effective.
Natalizumab is an immunosuppressant monoclonal antibody that blocks immune cell migration to treat MS and Crohn's disease.
This medication carries a boxed (black box) warning — the strongest type of FDA warning. Review the full prescribing information before use.
Key facts at a glance
- ATC
- L04AG03
- RxNorm
- 354770
- Generic
- Natalizumab
- Class
- atc-l04
- Brands
- Tyruko, Tysabri
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- injection
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 300mg every 4 weeks
- Maximum
- consult physician
- Frequency
- once monthly
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 300mg every 4 weeks
- Maximum
- consult physician
- Frequency
- once monthly
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 300mg every 4 weeks
- Maximum
- consult physician
- Frequency
- once monthly
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
10 groupspregnancy
first trimesteravoid if possible
discontinue therapy prior to pregnancy if possible; avoid use during pregnancy unless benefits significantly outweigh risks
regular fetal monitoring, ultrasound assessments
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
second trimesteravoid
continue avoidance; consider alternative therapies
fetal growth monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
third trimesteravoid
avoid use near delivery; potential risk of neonatal complications
fetal monitoring, assessment of neonatal immune function
Use of this medication in this population requires careful consideration of risks and benefits.
lactation
breastfeedingavoid
discontinue breastfeeding during treatment and for approximately 6 months after last dose
monitor infant for signs of infection
Use of this medication in this population requires careful consideration of risks and benefits.
pediatric_age
under 18 yearsnot established
not recommended for use in children and adolescents under 18 years due to limited safety and efficacy data
close monitoring if used off-label
geriatric
over 65 yearsno specific adjustment
use with caution; increased risk of infections in elderly; monitor closely for adverse effects
regular monitoring for infections, liver function
Use with caution and monitor for adverse effects.
renal_impairment
mild to moderateno dose adjustment required
no dose adjustment needed; monitor renal function regularly
periodic renal function monitoring
Use with caution and monitor for adverse effects.
renal_impairment
severeuse with caution
limited data in severe renal impairment; use only if benefits outweigh risks
close renal function monitoring
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderateuse with caution
use with caution; may cause elevated liver enzymes; monitor liver function
regular liver function tests
Use with caution and monitor for adverse effects.
hepatic_impairment
severenot recommended
avoid use in severe hepatic impairment due to risk of significant liver injury
frequent liver function monitoring if used
Use of this medication in this population requires careful consideration of risks and benefits.
Statistics and clinical data
FDA approval year
Initial FDA approval for Natalizumab
Drug class
Pharmacological classification
Common uses
Therapeutic indications
Mechanism of action
Pharmacodynamic properties
Natalizumab is FDA-approved for treating relapsing forms of multiple sclerosis, including clinically isolated syndrome, relapsing-remitting MS, and active secondary progressive MS. It is also used for moderate to severe Crohn's disease in patients who have not responded adequately to conventional therapies.
Natalizumab binds to the α4-subunit of α4β1 and α4β7 integrins on the surface of leukocytes (except neutrophils). This blocks the interaction between these immune cells and their counter-receptors on blood vessel walls, preventing immune cells from migrating into the central nervous system and gastrointestinal tract where they would cause inflammation and tissue damage.
Natalizumab carries a boxed warning for progressive multifocal leukoencephalopathy (PML), a rare but serious brain infection. It may also increase the risk of other infections and liver damage. Patients must be enrolled in a restricted distribution program and receive regular monitoring. Hypersensitivity reactions can occur during or after infusion.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy