Ibritumomab is a protein that targets white blood cells in the body. When ibritumomab is attached to a radioactive chemical, the radiation is delivered directly to the tumor (lymphoma).

Ibritumomab is used in combination with other medicines to treat non-Hodgkin's lymphoma.

Ibritumomab may also be used for purposes not listed in this medication guide.

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

Tell your doctor if you have ever had:

• any type of infection;
• bleeding or blood clotting problems;
• breathing problems; 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 or preleukemia. Ask your doctor about your specific risk.

You may need to have a negative pregnancy test before starting this treatment.

Both men and women using this medicine should use effective birth control to prevent pregnancy. Ibritumomab can harm an unborn baby or cause birth defects if the mother or father is using this medicine. Keep using birth control for at least 12 months after your last dose.

Tell your doctor right away if a pregnancy occurs while either the mother or the father is using ibritumomab.

Do not breastfeed while using this medicine, and for at least 6 months after your last dose.

Use In-111 Zevalin (Intravenous) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Life-threatening reactions may occur during the injection or within 24 hours afterward. Tell your caregivers or seek medical attention if you feel light-headed or short of breath, or if you have chest tightness or pain spreading to your jaw or shoulder.

Serious and sometimes fatal infections or skin reactions may occur during treatment with ibritumomab, and up to 4 months afterward. Call your doctor right away if you have:

• redness, ulcers, or skin changes where the medicine was injected;
• easy bruising, unusual bleeding, purple or red spots under your skin;
• unusual weakness or tiredness;
• low red blood cells (anemia)--pale skin, weakness, cold hands and feet; or
• low white blood cell counts--fever, mouth sores, skin sores, sore throat, cough, trouble breathing.

Common side effects may include:

• nausea, stomach pain, diarrhea;
• fever, cough;
• stuffy nose, sore throat, sinus pain; or
• feeling weak or tired.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.

Do not receive a "live" vaccine while using ibritumomab, and for at least 12 months after your treatment ends. The vaccine may not work as well during this time, and may not fully protect you from disease. Live vaccines include measles, mumps, rubella (MMR), polio, rotavirus, typhoid, yellow fever, varicella (chickenpox), zoster (shingles), and nasal flu (influenza) vaccine.