Name: Ibritumomab

Ibritumomab Overview

Ibritumomab is a prescription medication used in patients with cancer who have been treated with chemotherapy or with rituximab and have not gotten better or have had a relapse. Ibritumomab belongs to a group of drugs called monoclonal antibodies. When combined with a radioactive substance and given with rituximab, it works as a type of radioimmunotherapy to destroy cancer cells.

This medication comes as an injectable form to be given into the vein (IV) by a healthcare professional.

Common side effects include fatigue, nose and throat infection, and nausea. Do not drive or operate heavy machinery until you know how this medicaiton affects you.

Ibritumomab Interactions


Tell your doctor about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

  • medications that affect your platelets such as clopidogrel (Plavix), aspirin, prasugrel (Effient), ticagrelor (Brilinta), ticlopidine (Ticlid), abciximab (ReoPro), eptifibatide (Integrilin), tirofiban (Aggrastat), and cilostazol (Pletal)
  • blood thinners such as warfarin (Coumadin, Jantoven)

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



Ibritumomab and Lactation

Tell your doctor if you are breastfeeding or plan to breastfeed.

Ibritumomab has the potential to cross into human breast milk. Because of the possibility for adverse reactions in nursing infants from ibritumomab, a choice should be made whether to stop nursing or to stop use of this medication. The importance of the drug to the mother should be considered.


What should I discuss with my healthcare provider before receiving ibritumomab?

You should not receive this medicine if you are allergic to ibritumomab, or to radioactive chemicals or mouse proteins.

To make sure ibritumomab is safe for you, tell your doctor if you have:

  • liver disease;

  • kidney disease;

  • any type of infection;

  • lung or breathing problems;

  • bleeding or blood clotting problems;

  • low platelet counts;

  • low blood pressure;

  • a history of heart disease, heart attack, angina (chest pain), or irregular heart beats; or

  • if you take a blood thinner (warfarin, Coumadin) or other medicine to prevent blood clots.

Using ibritumomab may increase your risk of developing other types of cancer, such as leukemia. Ask your doctor about your specific risk.

Ibritumomab is made from human plasma (part of the blood) which may contain viruses and other infectious agents. Donated plasma is tested and treated to reduce the risk of it containing infectious agents, but there is still a small possibility it could transmit disease. Talk with your doctor about the risks and benefits of using this medication.

Do not use ibritumomab if you are pregnant. It could harm the unborn baby. Tell your doctor right away if you become pregnant during treatment. Use effective birth control while you are using this medicine and for at least 12 months after your treatment ends.

Ibritumomab can pass into breast milk and may harm a nursing baby. You should not breast-feed while using this medicine.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Consumer Information Use and Disclaimer

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else's drugs.
  • Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
  • Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Check with your pharmacist about how to throw out unused drugs.
  • Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about ibritumomab, please talk with your doctor, nurse, pharmacist, or other health care provider.
  • 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.

This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about ibritumomab. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using ibritumomab.

Review Date: October 4, 2017

Pharmacologic Category

  • Antineoplastic Agent, Anti-CD20
  • Antineoplastic Agent, Monoclonal Antibody
  • Radiopharmaceutical

Dosing Geriatric

Refer to adult dosing.

Dosing Hepatic Impairment

There are no dosage adjustments provided in the manufacturer's labeling.


Radiopharmaceutical; use appropriate precautions for handling and disposal. To prepare radiolabeled injection and determine radiochemical purity, follow detailed preparation guidelines provided by manufacturer. Use appropriate shielding during and after radiolabeling.


Rituximab: Administer the first infusion of rituximab at an initial rate of 50 mg/hour. If hypersensitivity or infusion-related events do not occur, escalate the infusion rate in 50 mg/hour increments every 30 minutes, to a maximum of 400 mg/hour. Immediately stop infusion for severe infusion reaction (discontinue ibritumomab regimen); less severe reactions may be managed by slowing or interrupting infusion. For less severe reactions, infusion may continue at one-half the previous rate upon improvement of patient symptoms. If infusion reaction did not occur in initial rituximab infusion, subsequent rituximab infusion can be administered at an initial rate of 100 mg/hour and increased in 100 mg/hour increments at 30-minute intervals, to a maximum of 400 mg/hour as tolerated. If infusion reaction occurred with initial rituximab infusion, initiate at 50 mg/hour with increases of 50 mg/hour increments every 30 minutes.

Y-90 ibritumomab: Begin within 4 hours of completion of rituximab infusion. Inject slowly, over 10 minutes through a 0.22 micron low protein binding in-line filter (filter placed between syringe and infusion port) into a free-flowing IV line. After injection, flush line with at least 10 mL normal saline. Avoid extravasation; closely monitor infusion site; if signs or symptoms of extravasation occur, stop infusion and restart in another limb.

Radiopharmaceutical; use appropriate precautions for handling and disposal.

Monitoring Parameters

CBC with differential and platelet counts weekly until recovery, or as clinically indicated. Platelet count must be obtained prior to day 7, 8, or 9; monitor for cytopenias (and related complications) for up to 3 months after use.

Hepatitis B virus screening recommendations (ASCO provisional clinical opinion update [Hwang 2015]): Screen for hepatitis B virus (HBV) infection with hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (anti-HBc) tests prior to treatment initiation; either a total anti-HBc (with both IgG and IgM) or anti-HBc IgG test should be used to screen for chronic or resolved HBV infection (do not use anti-HBc IgM as it may only confirm acute HBV infection). HBsAg negative/anti-HBc positive patients should be monitored for HBV reactivation with HBV DNA and ALT testing approximately every 3 months during treatment.

Monitor for signs of active hepatitis B infection (during and for up to 12 months after therapy completion). Monitor for infusion-related allergic reactions (typically within 30 to 120 minutes of administration), for extravasation during ibritumomab infusion; and for severe cutaneous and mucocutaneous reactions.

Pregnancy Risk Factor D Pregnancy Considerations

Animal reproduction studies have not been conducted. Based on the radioactivity, Y-90 ibritumomab may cause fetal harm if administered during pregnancy. IgG molecules are known to cross the placenta. Women of reproductive potential should avoid becoming pregnant during treatment with ibritumomab. Females of reproductive potential and males with female partners of reproductive potential should use effective contraception for at least 12 months following treatment. The effect on future fertility is unknown.

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience rhinitis, pharyngitis, diarrhea, nausea, vomiting, abdominal pain, muscle pain, lack of appetite, or night sweats. Have patient report immediately to prescriber signs of Stevens-Johnson syndrome/toxic epidermal necrolysis (red, swollen, blistered, or peeling skin [with or without fever]; red or irritated eyes; or sores in mouth, throat, nose, or eyes), signs of infection, signs of bleeding (vomiting blood or vomit that looks like coffee grounds; coughing up blood; blood in the urine; black, red, or tarry stools; bleeding from the gums; abnormal vaginal bleeding; bruises without a reason or that get bigger; or any bleeding that is very bad or that will not stop), severe dizziness, passing out, severe headache, loss of strength and energy, or injection site pain or irritation (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.