Leqembi Side Effects

Generic name: lecanemab

Medically reviewed by Drugs.com. Last updated on Apr 6, 2024.

Note: This document provides detailed information about Leqembi Side Effects associated with lecanemab. Some dosage forms listed on this page may not apply specifically to the brand name Leqembi.

Applies to lecanemab: intravenous solution.

Important warnings This medicine can cause some serious health issues

Intravenous route (solution)

Warning: Amyloid Related Imaging Abnormalities. Monoclonal antibodies directed against aggregated forms of beta amyloid, including lecanemab-irmb, can cause amyloid related imaging abnormalities (ARIA), characterized as ARIA with edema (ARIA-E) and ARIA with hemosiderin deposition (ARIA-H).

Incidence and timing of ARIA vary among treatments.

ARIA usually occurs early in treatment and is usually asymptomatic, although serious and life-threatening events rarely can occur.

Serious intracerebral hemorrhages, some of which have been fatal, have been observed in patients treated with class of medications.ApoE e4 Homozygotes. Patients who are apolipoprotein E e4 (ApoE e4) homozygotes (approximately 15% of Alzheimer's disease patients) treated with this class of medications, including lecanemab-irmb, have a higher incidence of ARIA, including symptomatic, serious, and severe radiographic ARIA, compared to heterozygotes and noncarriers.

Testing for ApoE e4 status should be performed prior to initiation of treatment to inform the risk of developing ARIA.

Prior to testing, prescribers should discuss with patients the risk ARIA across genotypes and the implications of genetic testing results.

Prescribers should inform patients that if genotype testing is not performed they can still be treated with lecanemab-irmb; however, it cannot be determined if they are ApoE e4 homozygotes and at higher risk for ARIA.Consider the benefit of lecanemab-irmb for the treatment of Alzheimer's disease and potential risk of serious adverse events associated with ARIA when deciding to initiate treatment with lecanemab-irmb.

Serious side effects of Leqembi

Along with its needed effects, lecanemab (the active ingredient contained in Leqembi) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking lecanemab:

More common side effects

• back pain
• blurred or changes in vision
• chest tightness
• chills
• confusion
• diarrhea
• dizziness
• dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• drowsiness
• feeling shaky
• fever
• flushing
• general feeling of discomfort or illness
• headache
• joint pain
• loss of appetite
• muscle aches and pain
• nausea and vomiting
• nervousness
• pale skin
• pounding in the ears
• runny nose
• seizures
• shivering
• slow or fast heartbeat
• sore throat
• sweating
• trouble breathing
• trouble sleeping
• unusual tiredness or weakness

Less common side effects

• cough or hoarseness
• lower back or side pain
• painful or difficult urination

Incidence not known

• cough
• difficulty swallowing
• dizziness
• fast heartbeat
• hives, itching, skin rash
• large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, sex organs
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue

For healthcare professionals

Applies to lecanemab: intravenous solution.

General adverse events

The most common adverse reactions reported were infusion-related reactions, headache, and amyloid related imaging abnormalities.^[Ref]

Cardiovascular

• Common (1% to 10%): Atrial fibrillation^[Ref]

Gastrointestinal

• Common (1% to 10%): Diarrhea^[Ref]

Hematologic

• Common (1% to 10%): Lymphopenia^[Ref]

Other

• Very common (10% or more): Infusion-related reactions (20%)^[Ref]

Respiratory

• Common (1% to 10%): Cough^[Ref]

Nervous system

• Very common (10% or more): Amyloid related imaging abnormalities (10%), headache (14%)^[Ref]

Frequently asked questions

• What are monoclonal antibodies?
• How do I decide between Leqembi and Kisunla?
• What is the controversy surrounding Leqembi?
• What's the mechanism of action for Leqembi (lecanemab-irmb)?
• Will insurance cover Kisunla treatment?
• How well does Kisunla work?
• How effective is Leqembi in delaying Alzheimer's disease?
• Is Leqembi eligible for Medicare or insurance coverage?

Further information

Leqembi side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer