This page presents data from the FDA Adverse Event Reporting System (FAERS) and the FDA-approved drug label. A report submitted to FAERS does not prove a drug caused the reported event. Always consult a healthcare provider about medications.
Tysabri is the brand name for natalizumab, a integrin receptor antagonist. According to the FDA-approved label, TYSABRI is an integrin receptor antagonist indicated for treatment of: Multiple Sclerosis (MS) TYSABRI is indicated as monotherapy for the treatment of relapsing forms of multiple sclerosis, to include clinically isolated syndrome, relapsing-remitting disease, and active secondar. FAERS contains 180,088 submissions naming this drug from 2004 through 2026; the top three reactions cited are fatigue, multiple sclerosis relapse, and headache.
Most-Reported Reactions
Counts of the reactions most often cited in FAERS submissions that named Tysabri. Inclusion here does not establish causation - submitters describe what was observed, not what was confirmed. One submission can list several reactions, so the totals exceed the report count.
Patient Demographics
Patient sex and age across the FAERS submissions that named Tysabri. Percentages here are computed only from submissions where these fields were filled in - many leave them blank.
By Sex
By Age Group
Severity Outcomes
Severity flags recorded across the 180,088 FAERS submissions that named Tysabri. Each bar shows the count of those reports carrying that flag. A single case can carry more than one (a hospitalization that became life-threatening, for example), so these bars are independent rates - they don't sum to 100%. Inclusion of a case under any flag does not establish that the drug caused the outcome.
Submissions Per Quarter
Quarterly count of FAERS submissions that named Tysabri. Ups and downs on this chart can track prescribing volume, news cycles, or shifts in how reports get filed, rather than the drug becoming safer or more dangerous.
From the FDA-Approved Label
Excerpts from the official FDA-approved prescribing information for Tysabri. This is the authoritative source on indications, warnings, and known adverse reactions.
Indications
1 INDICATIONS AND USAGE TYSABRI is an integrin receptor antagonist indicated for treatment of: Multiple Sclerosis (MS) TYSABRI is indicated as monotherapy for the treatment of relapsing forms of multiple sclerosis, to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults. TYSABRI increases the risk of PML [See Warnings and Precautions ( 5.1 ) ]. When initiating and continuing treatment with TYSABRI, physicians should consider whether the expected benefit of TYSABRI is sufficient to offset this risk. ( 1.1 ) Crohn's Disease (CD) TYSABRI is indicated for inducing and maintaining clinical response and remission in adult patients with moderately to severely active Crohn's disease with evidence of inflammation who have had an inadequate response to, or are unable to tolerate, conventional CD therapies and inhibitors of TNF-α. ( 1.2 ) Important Limitations: In CD, TYSABRI should not be used in combination with immunosuppressants or inhibitors of TNF-α. ( 1.2 ) 1.1 Multiple Sclerosis (MS) TYSABRI is indicated as monotherapy for the treatment of relapsing forms of multiple sclerosis, to include clinically isolated syndrome, r...
Adverse Reactions (from label)
6 ADVERSE REACTIONS The following serious adverse reactions are described below and elsewhere in the labeling: Progressive Multifocal Leukoencephalopathy (PML) [see Warnings and Precautions ( 5.1 )] Herpes Infections [see Warnings and Precautions ( 5.3 )] Hepatotoxicity [see Warnings and Precautions ( 5.4 )] Hypersensitivity/Antibody Formation [see Warnings and Precautions ( 5.5 )] Immunosuppression/Infections [see Warnings and Precautions ( 5.6 )] Hematological Abnormalities [see Warnings and Precautions ( 5.8 )] Most common adverse reactions (incidence ≥ 10%): MS - headache, fatigue, arthralgia, urinary tract infection, lower respiratory tract infection, gastroenteritis, vaginitis, depression, pain in extremity, abdominal discomfort, diarrhea NOS, and rash ( 6.1 ) CD - headache, upper respiratory tract infections, nausea, and fatigue ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Biogen at 1-800-456-2255 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical t...
AdverseEvent.ai is not affiliated with the FDA. Adverse-event counts come from the FDA Adverse Event Reporting System (FAERS). Drug labels come from the FDA drug label dataset. A report submitted to FAERS does not prove a drug caused the reported event — always consult a healthcare provider about medications. This site is for informational purposes only and is not medical advice.
