From the FDA Drug Label
Call your healthcare provider or go to the nearest hospital emergency room right away if you have any of the symptoms listed above.
You should call 911 after receiving Leqembi if you experience any of the following symptoms:
- Headache
- Confusion
- Dizziness
- Vision changes
- Nausea
- Difficulty walking
- Seizures These symptoms can be indicative of ARIA (amyloid-related imaging abnormalities) or other serious side effects, and immediate medical attention is necessary 1.
From the Research
You should call 911 immediately after receiving Leqembi (lecanemab) if you experience symptoms of a serious allergic reaction, sudden severe headache, confusion, seizures, vision changes, weakness on one side of the body, difficulty speaking, or loss of consciousness, as these could indicate ARIA (Amyloid-Related Imaging Abnormalities) or a more severe brain hemorrhage, which are known potential side effects of Leqembi 2. These symptoms can occur at any time during treatment, but are more common within the first few months. It is essential to seek immediate medical attention if you experience any of these symptoms, as brain swelling or bleeding requires prompt treatment.
Key Symptoms to Watch For:
- Serious allergic reaction (difficulty breathing, severe dizziness, or swelling of the face/throat)
- Sudden severe headache
- Confusion
- Seizures
- Vision changes
- Weakness on one side of the body
- Difficulty speaking
- Loss of consciousness
Importance of Immediate Action:
According to a recent study published in 2024, ARIA can be associated with ischemic strokes, highlighting the need for prompt medical attention if symptoms occur 2. Another study published in the same year found that ARIA typically occurs within the first few months of treatment, but can happen at any time 3.
Pre-Treatment Discussions and Monitoring:
Before starting Leqembi, your doctor should have discussed these risks with you and scheduled regular MRI monitoring throughout treatment to detect ARIA early 4. However, emergency symptoms require immediate action regardless of your next scheduled appointment.
Risk Factors for ARIA:
Certain risk factors, such as a positive Apoε4 carrier status and prior multiple cerebral microhemorrhages, can increase the likelihood of developing ARIA 5. Your doctor should have considered these risk factors before prescribing Leqembi and developed a plan for monitoring and managing potential side effects.