Alemtuzumab treats multiple sclerosis and a certain type of leukemia. May increase your risk of developing an infection. Tell your doctor if you notice a fever.

Alemtuzumab Overview


Alemtuzumab is a prescription medication used to treat B-cell chronic lymphocytic leukemia (BCLL)- a type of cancer. Alemtuzumab is also used for the treatment of patients with relapsing forms of multiple sclerosis (MS). Alemtuzumab works by helping the immune system find and destroy cancer cells and it belongs to a group of drugs called monoclonal antibodies which target specific types of cancer cells. 

This medication comes in a liquid form and is injected intravenously (into a vein) by your doctor or healthcare provider. Your dose may require gradual increases beginning with low doses daily and eventually higher doses three times a week. A full course of alemtuzumab is usually about 12 weeks long.

Some of the common side effects of alemtuzumab include decreased blood count, skin rash, and an increased risk of infection.


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  • Other
  • Leukemia, Lymphocytic, Chronic, B-cell

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  • A month or so
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Alemtuzumab Cautionary Labels


Uses of Alemtuzumab

Alemtuzumab is a prescription anti-cancer medication that is used to treat patients with B-cell chronic lymphocytic leukemia (a type of cancer of the blood). Alemtuzumab is also used for the treatment of patients with relapsing forms of multiple sclerosis (MS).

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

Alemtuzumab Brand Names

Alemtuzumab may be found in some form under the following brand names:

Alemtuzumab Drug Class

Alemtuzumab is part of the drug class:

Side Effects of Alemtuzumab

Alemtuzumab can cause serious side effects. See "Alemtuzumab Precautions" section.

The most common side effects of alemtuzumab include:

  • decreased blood counts. Alemtuzumab can cause a decrease in neutrophils (a type of white blood cells important in fighting in bacterial infections), red blood cells (blood cells that carry oxygen to the tissues), and platelets (important for clotting and to control bleeding).
  • infusion reactions sometimes serious. These side effects often occur during or around the time the medication is administered:
    • fever
    • chills
    • itching
    • rash
    • increased heart rate
    • decreased breathing rate
  • infection including uncommon viral infections. Call your doctor right away if you get any of the following signs of infection:
    • fever
    • chills or shivering
    • painful swallowing
    • sore throat
    • cough that brings up mucus
    • burning or pain on urination
    • redness or swelling at intravenous site
  • bleeding or bruising. Tell your doctor about any signs or symptoms of bleeding or bruising.
  • diarrhea
  • nausea
  • vomiting
  • constipation
  • stomach pain
  • insomnia 
  • anxiety
  • injection site reactions. Reactions may include redness, swelling, pain, tissue damage at the site of injection.

Tell your doctor if you have any side effect that bothers you or that does not go away. These are not all the possible side effects of alemtuzumab. For more information, ask your doctor or pharmacist.

Call your doctor for medical advice about side effects. 

Alemtuzumab Interactions

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. No official interaction studies have been performed with alemtuzumab but because alemtuzumab can reduce your body's ability to fight off infection tell your doctor before taking alemtuzumab if you are receiving:

  • Live and weakened viral vaccines including:
    • ​Flu vaccines
    • Mump vaccines
    • Measle vaccines
    • Rubella vaccines
    • Polio vaccines
    • Rotavirus vaccines
    • Chickenpox vaccines
    • Shingles vaccines
    • Typhoid vaccines
    • Yellow fever vaccines

This is not a complete list of alemtuzumab drug interactions. Ask your doctor or pharmacist for more information.

Alemtuzumab Precautions

Alemtuzumab can cause some serious side effects that you should know. These side effects include:

  • Low blood counts (cytopenia): In some cases, alemtuzumab can cause rare but serious and even fatal cases of low blood counts. The risk of low blood counts is greater when the given dose is more than recommended amount or when alemtuzumab is taken for longer than recommended. Alemtuzumab should be stopped if certain blood counts fall into dangerously low levels. You should ask your doctor or pharmacist about the following before taking alemtuzumab:
    • Low red blood cells (anemia)
    • Low platelets (thrombocytopenia) 
    • Low bone marrow activity (myelosuppression)
    • Immature cell production (aplasia)
    • Low overall blood cell production (pancytopenia)
  • Infusion reactions: These side effects often occur during or shortly after starting a dose of alemtuzumab. These are generally worst during the first week of treatment but can occur later in treatment too. These side effects include:
    • Fever
    • Itching
    • Low blood pressure
    • Nausea
    • Vomiting
    • Difficulty breathing
    • Chills
    • Fainting
    • Swelling
    • Heart problems including irregular heartbeat and heart attack
    • Inflammation and fluid retention in the lungs
  • A serious lung problem called Acute Respiratory Distress Syndrome (ARDS). Get medical help right away if you have any of these symptoms of Acute Respiratory Distress Syndrome (ARDS):
    • Abrupt fever
    • Severe shortness of breath
    • Prolonged trouble breathing
  • Increased risk of serious infections: Alemtuzumab weakens the body's immune system and affects your ability to fight infections. Serious infections can happen with alemtuzumab and can sometimes lead to death. Serious infections can include:
  • Viral infections. Certain viruses can live in your body and cause active infections when your immune system is weak. Viral infections that can happen with mycophenolate mofetil include:
    • Shingles, other herpes infections, and cytomegalovirus (CMV). CMV can cause serious tissue and blood infections.
    • BK virus. BK virus can affect how your kidney works and cause your transplanted kidney to fail.

Do not use alemtuzumab if you are allergic to any of the ingredients it contains. 

Alemtuzumab should not be given to pregnant women or women who are trying to become pregnant unless absolutely necessary, because alemtuzumab may cause harm to an unborn child. Women should avoid becoming pregnant while being treated with alemtuzumab.

Alemtuzumab Food Interactions

Medications can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of alemtuzumab, there are no specific foods that you must exclude from your diet.

Inform MD

Tell your doctor about all of your medical conditions, if you:

  • notice bruising, swelling, bleeding, or any other unexpected reactions while taking alemtuzumab
  • expect to receive any vaccines before, during, or after treatment with alemtuzumab

Tell your doctor about all of the medicines you are taking including prescription and nonprescription medicines, vitamins and herbal supplements.

Alemtuzumab and Pregnancy

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

This medication falls into category C. In animal studies, pregnant animals were given this medication and had some babies born with problems. No well-controlled studies have been done in humans. Therefore, this medication may be used if the potential benefits to the mother outweigh the potential risks to the unborn child.

Alemtuzumab and Lactation

Tell your doctor if you are breastfeeding or plan to breastfeed. It is not known if alemtuzumab passes into your breast milk. You and your doctor should decide whether you will stop breastfeeding or not take alemtuzumab.

Alemtuzumab Usage

Alemtuzumab is given to you through your veins (blood vessels).

• Your doctor will prescribe alemtuzumab in an amount that is right for you. 
• Your doctor will often treat you with several medications for your cancer
• It is very important that you follow your doctor's instructions closely. 
• Some medicines may be given to you before alemtuzumab to help prevent nausea, vomiting, itching, and other side effects

Initial treatment:

Alemtuzumab is given through a thin plastic tube put into a vein (intravenous infusion or I.V.) and injected over 2 hours. You will be watched by a healthcare provider during this time. These injections will likely continue for several days before your doctor may change your dose amount or dose frequency.

Later treatment:

Alemtuzumab is usually given for a total of 12 weeks. After initial treatment, alemtuzumab doses are often increased. The number of times you may receive alemtuzumab per week may decrease over time depending on your doctor's orders. At maximum dosage, alemtuzumab is usually given three times a week with a day of rest between each injection.

Alemtuzumab Dosage

This medication is usually given by infusion into a vein over at least 2 hours by a doctor, nurse or other health care professional. It is usually given every day or three times a week with other medications to reduce alemtuzumab's side effects. How quickly your dose increase depends on how well you are able to tolerate its side effects. The maximum recommended dose is no more than 30mg per day and no more than 90mg per week.

Alemtuzumab Overdose

If you take too much this medication, call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.

If this medication is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if an overdose is suspected, seek emergency medical attention.

Other Requirements

  • It is important for you to keep all appointments. Call your doctor if you must miss an appointment. There may be special instructions for you.
  • Your doctor may change how often you get alemtuzumab, how much you get, or how long the infusion will take.
  • You and your doctor will discuss how many times you will get alemtuzumab.

Alemtuzumab FDA Warning

Cytopenias: Serious, including fatal, pancytopenia/marrow hypoplasia, autoimmune idiopathic thrombocytopenia, and autoimmune hemolytic anemia can occur in patients receiving alemtuzumab. Single doses of alemtuzumab greater than 30 mg or cumulative doses greater than 90 mg per week increase the incidence of pancytopenia.

Infusion Reactions: Alemtuzumab administration can result in serious, including fatal, infusion reactions. Carefully monitor patients during infusions and withhold alemtuzumab for Grade 3 or 4 infusion reactions.

Gradually escalate alemtuzumab to the recommended dose at the initiation of therapy and after interruption of therapy for 7 or more days.

Infections: Serious, including fatal, bacterial, viral, fungal, and protozoan infections can occur in patients receiving alemtuzumab. Administer prophylaxis against Pneumocystis jiroveci pneumonia (PCP) and herpes virus infections.