Tysabri (Natalizumab)
Provider Summary
Primary Uses
Relapsing forms of multiple sclerosis; Crohn’s disease in selected cases per label and risk-benefit assessment.
Mechanism of action
Integrin inhibitor that reduces leukocyte adhesion and migration into CNS/GI tissue.
Pre-treatment / baseline requirements
PML risk stratification (JC virus antibody status, prior immunosuppressant use, treatment duration); enrollment in required restricted distribution/monitoring program when applicable; baseline MRI per neurologist; screen for active infection.
Common side effects
Headache, fatigue, arthralgia, infusion reactions.
Serious adverse effects / key risks
Boxed warning: progressive multifocal leukoencephalopathy (PML); serious infections; hypersensitivity.
Referral requirements
Standard infusion referral form + drug-specific checklist
Program requirements
Risk-mitigation/monitoring program participation and PML risk stratification (including JCV antibody testing) are typically required; follow specialist protocol.
Patient & Caregiver Education
What it treats
Relapsing forms of multiple sclerosis; Crohn’s disease in selected cases
How it works
Blocks immune-cell trafficking (gut-selective for some conditions).
Before treatment
Tell your clinician if you have an active infection/fever, are pregnant/planning pregnancy, or have major heart/nerve problems. Depending on the medication, you may need labs or screening tests (e.g., TB/hepatitis) and a vaccine review.
Common side effects
Headache, fatigue, arthralgia, infusion reactions.
Get urgent help for
Boxed warning: progressive multifocal leukoencephalopathy; serious infections; hypersensitivity.
On treatment day
plan to stay for monitoring. If you feel dizzy, drowsy, or unwell afterward, do not drive and follow your clinician’s instructions.