Ibritumomab injection is used with rituximab (Rituxan) to treat certain types of non-Hodgkin's lymphoma (NHL; cancer that begins in the cells of the immune system) that has not improved or that has worsened after treatment with other medications. It is also used to treat certain types of NHL in people who have improved after treatment with other chemotherapy medications. Ibritumomab injection is in a class of medications called monoclonal antibodies with radioisotopes. It works by attaching to cancer cells and releasing radiation to damage the cancer cells.

Several hours before each dose of ibritumomab injection, a medication called rituximab (Rituxan) is given. Some patients have had serious or life-threatening allergic reactions while they received rituximab or shortly after they received rituximab. These reactions have occurred most often with the first dose of rituximab. Some patients have died within 24 hours after receiving rituximab. Tell your doctor if you are allergic to rituximab or medications made from murine (mouse) proteins, or if you are not sure if a medication you are allergic to is made from murine proteins. Also tell your doctor if you have ever been treated with a medication made from murine proteins. If so, you may be more likely to have an allergic reaction to rituximab. Your doctor will order tests to see if you are likely to have an allergic reaction to rituximab.

Your doctor will give you medication before you receive rituximab to help prevent reactions to rituximab. If you experience a reaction to rituximab, your doctor may stop giving you the medication for a time or may give it to you more slowly. If the reaction is serious, your doctor will stop the rituximab infusion and will not continue your treatment with ibritumomab injection. Tell your doctor right away if you experience any of the following symptoms during or shortly after your treatment with rituximab: cough; difficulty breathing or swallowing; tightening of the throat; hives; itching; swelling of the eyes, face, lips, tongue, mouth, or throat; pain in the chest, jaw, arm, back, or neck; confusion; loss of consciousness; fast heartbeat; sweating; pale skin; fast breathing; decreased urination; or cold hands and feet.

Treatment with rituximab and ibritumomab injection may cause a severe decrease in the number of blood cells in your body. This decrease may happen 7 to 9 weeks after your treatment and may last for 12 weeks or longer. This decrease may cause serious or life-threatening infections or bleeding. Your doctor will not give you ibritumomab injection if your blood cells have been severely affected by cancer, if you have had a bone marrow transplant, if you have been unable to produce enough stem cells (cells found in the bone marrow that can mature to form any type of blood cell) to have a bone marrow transplant, or if you already have a low number of blood cells. Tell your doctor if you are taking any of the following medications: anticoagulants ('blood thinners') such as warfarin (Coumadin, Jantoven); aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) and naproxen (Aleve); and clopidogrel (Plavix). If you have any of the following symptoms, call your doctor right away: pale skin; weakness; unusual bruising or bleeding; purple spots or patches on the skin; black or bloody stools; vomit that is bloody or looks like coffee grounds; diarrhea; or sore throat, fever, chills, cough, or other signs of infection.

Treatment with rituximab and ibritumomab injection may cause serious or fatal skin reactions. These reactions may occur as soon as a few days after treatment or as long as 4 months after treatment. Tell your doctor right away if you develop blisters on your skin or on the inside of your mouth or nose, a rash, or peeling of the skin. Your doctor will not give you any more ibritumomab injection if you develop these symptoms.

After you receive your first dose of ibritumomab injection, your doctor will order imaging scans (tests that show a picture of all or part of the inside of the body) to see how the medication has spread through your body. If the medication has not spread through your body as expected, you will not receive your second dose of ibritumomab injection.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain tests during your treatment and for up to 3 months after your treatment to check your body's response to ibritumomab injection.

Talk to your doctor about the risks of receiving ibritumomab injection.

Ibritumomab injection comes as a liquid to be injected into a vein over 10 minutes by a doctor who has been trained to treat patients with radioactive medication. It is given as part of a specific cancer treatment regimen. On the first day of the treatment regimen, a dose of rituximab is given and the first dose of ibritumomab injection is given no more than 4 hours afterward. Imaging scans to see how ibritumomab injection has spread through the body are performed 48 to 72 hours after the dose of ibritumomab injection is given. Additional scans may be performed if needed during the next several days. If the results of the scan(s) show that ibritumomab injection has spread through the body as expected, a second dose of rituximab and a second dose of ibritumomab injection will be given 7 to 9 days after the first doses were given.

Before receiving ibritumomab injection,

• tell your doctor and pharmacist if you are allergic to ibritumomab, any of the medications mentioned in the IMPORTANT WARNING section, any other medications, or any of the ingredients in ibritumomab injection. Ask your doctor or pharmacist for a list of the ingredients.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention the medications listed in the IMPORTANT WARNING section. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have or have ever had any medical condition.
• tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while you are receiving ibritumomab. If you are female, you will need to take a pregnancy test before starting treatment and use birth control to prevent pregnancy during your treatment and for 12 months after your final dose. If you are a male with a female partner, use birth control to prevent pregnancy during your treatment and for 12 months after your final dose. If you or your partner become pregnant while receiving ibritumomab injection, call your doctor immediately. Ibritumomab injection may harm the fetus.
• tell your doctor if you are breastfeeding or plan to breastfeed. You should not breastfeed while receiving ibritumomab and for 6 months after your final dose.
• you should know that this medication may decrease fertility in men and women. Talk to your doctor about the risks of receiving ibritumomab.
• if you are having surgery, including dental surgery, tell the doctor or dentist that you have received ibritumomab injection.
• do not have any vaccinations during treatment and for 12 months after your final dose without first talking to your doctor.
• you should know that the radioactivity in the second dose of ibritumomab injection may be present in your body fluids for up to a week after you receive the dose. To prevent the radioactivity from spreading to people who are in close contact with you, you should be sure to wash your hands thoroughly after using the bathroom, use a condom every time you have sexual intercourse, and avoid deep kissing. Follow these precautions during your treatment and for 7 days after you receive your second dose of ibritumomab injection.
• you should know that ibritumomab injection contains albumin (a product that is made from live donor blood). Although there is an extremely small chance that viruses may be spread through the blood, no cases of viral diseases from this product have been reported.
• you should know that if you receive ibritumomab injection, your body may develop antibodies (substances in the blood that help the immune system recognize and attack foreign substances) to murine proteins. If you develop these antibodies, you may have an allergic reaction when you take medications made from murine proteins, or these medications might not work well for you.After your treatment with ibritumomab injection, be sure to tell all of your doctors that you have been treated with ibritumomab injection.

Call your doctor right away if you cannot keep an appointment to receive ibritumomab injection.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include the following:

• pale skin
• weakness
• shortness of breath
• excessive tiredness
• unusual bruising or bleeding
• purple spots or patches on the skin
• sore throat, fever, chills, cough, and other signs of infection

Unless your doctor tells you otherwise, continue your normal diet.

Ibritumomab injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• nausea
• vomiting
• stomach pain or swelling
• constipation
• heartburn
• loss of appetite
• headache
• anxiety
• dizziness
• difficulty falling asleep or staying asleep
• back, joint, or muscle pain
• flushing

Some side effects can be serious. If you experience any of the symptoms listed in the IMPORTANT WARNING section or any of the following symptoms, call your doctor immediately:

• redness, tenderness, or an open wound in the area where the medication was injected

Some people who received ibritumomab injection developed other forms of cancer such as leukemia (cancer that begins in the white blood cells) and myelodysplastic syndrome (condition in which blood cells do not develop normally) during the first several years after they received the medication. Talk to your doctor about the risks of receiving this medication.

Ibritumomab injection may cause other side effects. Call your doctor if you have any unusual problems while receiving this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

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

Ask your doctor or pharmacist any questions you have about ibritumomab injection.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

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