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Lecanemab-irmb Injection

pronounced as (lek an' e mab)


Lecanemab-irmb may cause a potentially serious reaction called amyloid related imaging abnormalities (ARIA), which most commonly includes temporary swelling in areas of the brain; small spots of bleeding on the surface of the brain and, infrequently, larger areas of bleeding in the brain may also occur. Swelling in areas of the brain usually does not cause symptoms and usually resolves over time. If you experience any of the following symptoms, tell your doctor immediately or get emergency medical treatment: headache, confusion, dizziness, vision changes, nausea, difficulty walking or loss of balance, or seizures.

The chance that you will develop ARIA during your treatment with lecanemab-irmb may be higher if you have a genetic (inherited) risk factor. Your doctor may order a blood test to help decide if this medication is right for you. Tell your doctor if you are taking medications that may cause bleeding.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain tests such as magnetic resonance imaging (MRI; a medical test that uses powerful magnets to take pictures of the inside of the body) scans before and during treatment to check your body's response to lecanemab-irmb.

Why is this medication prescribed?

Lecanemab-irmb injection is used to reduce amyloid beta plaque, a protein found in the brain of people with Alzheimer's disease (a brain disorder that affects the ability to remember, think clearly, communicate, and perform daily activities and may cause changes in mood and personality) in patients with mild disease. It is used to treat people with mild cognitive impairment (MCI) or mild dementia. Lecanemab-irmb is in a class of medications called monoclonal antibodies. It works by reducing amyloid beta plaques, abnormal proteins that develop in the brain and contribute to the progression of Alzheimer's disease.

How should this medicine be used?

Lecanemab-irmb injection comes as a solution (liquid) to be infused intravenously by a doctor or nurse in a healthcare setting. It is usually given every 2 weeks in an infusion that lasts about an hour.

Lecanemab-irmb injection may cause a severe reaction during or shortly after the infusion of the medication. A doctor or nurse will monitor you carefully while you are receiving the medication. You may be given other medications to help prevent and treat reactions. If you experience any of the following symptoms, tell your doctor immediately: fever, chills, body aches, joint pain, nausea, vomiting, dizziness or lightheadedness, feeling of racing heart rate or chest pounding, or difficulty breathing or shortness of breath.

Your doctor may need to interrupt your treatment or stop your treatment depending on your response to the medication and any side effects that you experience. Be sure to tell your doctor how you are feeling during your treatment.

Lecanemab-irmb controls Alzheimer's disease but does not cure it. Do not stop receiving lecanemab-irmb without talking to your doctor.

Other uses for this medicine

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What special precautions should I follow?

Before receiving lecanemab-irmb injection,

  • tell your doctor and pharmacist if you are allergic to lecanemab-irmb, any other medications, or any of the ingredients in lecanemab-irmb injection. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
  • tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take while receiving lecanemab-irmb injection. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • The following nonprescription or herbal products may interact with lecanemab-irmb injection: aspirin. Be sure to let your doctor and pharmacist know that you are taking this medication before you start receiving lecanemab-irmb injection. Do not start this medication while receiving lecanemab-irmb injection without discussing with your healthcare provider.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking lecanemab-irmb, call your doctor.

What special dietary instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What should I do if I forget a dose?

If you miss an appointment to receive lecanemab-irmb injection, you should call your healthcare provider as soon as possible.

What side effects can this medication cause?

Lecanemab-irmb injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • cough
  • diarrhea

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or get emergency medical treatment:

  • hives; rash; itching; swelling of the lips, tongue, or throat; shortness of breath or difficulty breathing

Lecanemab-irmb may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online ( or by phone (1-800-332-1088).

What other information should I know?

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

Brand names

  • Leqembi®
Last Revised - 11/15/2023