Skip to main content

Alemtuzumab (Lemtrada)

Generic name: Alemtuzumab (Lemtrada) [ ay-lem-TU-zoo-mab ]
Brand name: Lemtrada
Drug class: CD52 monoclonal antibodies

Medically reviewed by Last updated on Oct 31, 2023.


  • Severe and sometimes life-threatening infusion reactions have happened. You will be closely watched during the infusion and for some time after. Severe infusion reactions may also happen up to 48 hours or longer after the infusion. Tell your doctor right away if you have chest pain; passing out; fast or slow heartbeat, or abnormal heartbeat; fever; hives; itching; rash; severe headache or dizziness; shortness of breath, wheezing, or other trouble breathing; swelling of the mouth, face, lips, throat, or tongue; tightness in the chest or throat; abnormal hoarseness; or coughing up blood.
  • Other infusion reactions include change in taste, chills, dizziness, flushing, upset stomach, pain, feeling tired, or not able to sleep. Talk with the doctor.
  • This medicine may cause very bad and sometimes deadly autoimmune problems like some blood problems. Side effects may happen while you get alemtuzumab (lemtrada) and for 4 years after you stop treatment. You will need to have your blood work and urine checked while getting alemtuzumab (lemtrada) and after getting it as you have been told by your doctor. Talk with your doctor.
  • Very bad and sometimes deadly infections have happened in patients who take alemtuzumab (lemtrada). If you have any infection, are taking antibiotics now or in the recent past, or have had many infections, talk with your doctor.
  • Rarely, strokes and tears in blood vessels in the head and neck have happened with alemtuzumab when used for MS (multiple sclerosis). Most of the time, this happened within 1 day after getting alemtuzumab (lemtrada) but can happen a few days after treatment. These health problems can lead to long-term disability and can be deadly. Closely read the part in this leaflet which lists when to call your doctor.
  • This medicine may raise the chance of cancer like thyroid cancer, skin cancer, and lymphoma. Have your skin checked and other lab tests done as you have been told by your doctor. Talk with your doctor.

Uses of Alemtuzumab:

What do I need to tell my doctor BEFORE I take Alemtuzumab?

This is not a list of all drugs or health problems that interact with alemtuzumab (lemtrada).

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take alemtuzumab (lemtrada) with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take Alemtuzumab?

How is this medicine (Alemtuzumab) best taken?

Use alemtuzumab (lemtrada) as ordered by your doctor. Read all information given to you. Follow all instructions closely.

What do I do if I miss a dose?

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

What are some other side effects of Alemtuzumab?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at

If OVERDOSE is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out Alemtuzumab?

Consumer Information Use and Disclaimer

Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.