The most commonly reported side effects of natalizumab include multiple sclerosis relapse, fatigue, and fatigue, based on 179,695 FDA adverse event reports from 2004 to 2025. 2.3% of reports found the drug to be ineffective.
Percentages show how often each reaction appears relative to total reports for natalizumab.
These are voluntary reports and do not establish that natalizumab caused these reactions.
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Other drugs that appear in adverse event reports alongside natalizumab. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.
Also suspected
Taken alongside
Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.
75.8% of natalizumab adverse event reports involve female patients and 22.6% involve male patients. The largest age group is adult at 94%. These figures reflect who reports side effects, not underlying risk.
Sex
Age group
Conditions and purposes for which patients were taking natalizumab when the adverse event was reported.
Showing 15 of 154 indications
Natalizumab is sold under brand names including Tysabri, Tyruko.
An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.
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