The most commonly reported side effects of lecanemab include headache, amyloid related imaging abnormality-oedema/effusion, and amyloid related imaging abnormality-microhaemorrhages and haemosiderin deposits, based on 3,038 FDA adverse event reports from 2015 to 2025.
Percentages show how often each reaction appears relative to total reports for lecanemab.
These are voluntary reports and do not establish that lecanemab caused these reactions.
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Other drugs that appear in adverse event reports alongside lecanemab. 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.
53.1% of lecanemab adverse event reports involve female patients and 37.3% involve male patients. The largest age group is elderly at 89%. These figures reflect who reports side effects, not underlying risk.
Sex
Age group
Conditions and purposes for which patients were taking lecanemab when the adverse event was reported.
Lecanemab is sold under the brand name Leqembi Iqlik.
An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.
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