This medication is used to treat Alzheimer's disease. It is thought to work by decreasing a certain substance (amyloid beta) that builds up in the brain of a person with Alzheimer's disease. Lecanemab belongs to a class of drugs known as monoclonal antibodies. This medication is not a cure for Alzheimer's disease. It may help slow down worsening of this disease and may delay disability.

Read the Medication Guide provided by your pharmacist before you start using lecanemab and each time you receive an injection. If you have any questions, ask your doctor or pharmacist.

This medication is given by injection into a vein as directed by your doctor, usually every 2 or 4 weeks. The injection is given by a health care professional, usually over 1 hour. The dosage is based on your medical condition, weight, and response to treatment.

Infusion reactions may happen during the infusion of this drug and for some time afterward. Your doctor may prescribe other medications before each treatment to help prevent these side effects. Tell your doctor right away if you have any symptoms of infusion reactions such as shortness of breath, fever, chills, joint pain, nausea, vomiting, or dizziness. Your doctor may slow down or stop your infusion for some time.

Use this medication regularly to get the most benefit from it. To help you remember, mark your calendar with a reminder.

See also Warning and How to Use sections.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before using lecanemab, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

It is unknown if this medication passes into breast milk. Consult your doctor before breastfeeding.

See also Warning section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Lab and/or medical tests (such as genetic testing, MRI scans, cognitive assessment) should be done before you start using this medication and while you are using it. Keep all medical and lab appointments.

It is important to get each dose of this medication as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule.

Not applicable. This medication is given in a hospital or clinic and will not be stored at home.