Generic Name: tositumomab (TOE si too MOE mab)
Brand Name: Bexxar Dosimetric, BexxarTherapeutic
What is tositumomab?
Tositumomab is a monoclonal antibody that is linked with radioactive iodine I-131. Monoclonal antibodies are made to target and destroy only certain cells in the body. This may help to protect healthy cells from damage.
Tositumomab is used to treat certain forms of non-Hodgkin's lymphoma. It is usually given after other medications have been tried without successful treatment.
Tositumomab may also be used for purposes not listed in this medication guide.
What is the most important information I should know about tositumomab?
Serious and sometimes fatal allergic reactions may occur during treatment with tositumomab. Tell your caregiver right away if you feel dizzy, nauseated, light-headed, sweaty, or have a fever, chills, chest tightness, wheezing, or trouble breathing.
Tositumomab can lower blood cells that help your body fight infections and help your blood to clot. This can make it easier for you to bleed from an injury or get sick from being around others who are ill. Your blood will need to be tested often.
After you are treated with tositumomab, your body will retain radioactive material for several days. Follow your caregivers' instructions about how to avoid exposing other people to radiation until this effect wears off.
What should I discuss with my health care provider before I receive tositumomab?
You should not receive this medicine if you are allergic to mouse proteins, or if you have ever had an allergic reaction to a monoclonal antibody.
To make sure tositumomab is safe for you, tell your doctor if you have:
kidney disease; or
severe bone marrow suppression.
Tositumomab can cause damage to the thyroid gland of an unborn baby if the mother receives this medication during pregnancy. You should not receive this medication if you are pregnant.
Tositumomab can be harmful to an unborn baby whether the father or the mother receives this medication at the time of conception. Use effective birth control to prevent pregnancy during your treatment, whether you are a man or a woman. Continue using birth control for at least 12 months after you have received tositumomab.
Tositumomab can pass into breast milk and may harm a nursing baby. You should not breast-feed while you are using tositumomab.
Some people treated with tositumomab later developed leukemia or other cancers. However, it has not been determined whether this medication actually increases the risk of causing other cancers. Talk with your doctor about your individual risk.
How is tositumomab given?
Tositumomab is injected into a vein through an IV. You will receive two different injections (tositumomab, and iodine I-131 tositumomab) given one at a time. The first injection is given over at least 60 minutes and the second injection is given over at least 20 minutes.
The tositumomab treatment is usually given in two steps over a span of 7 days. In the first step, you will receive the two injections just before you undergo an X-ray scan of your entire body. This scan will show your doctor how well the radioactive ingredients of tositumomab are circulating throughout your body. You may also need additional scans over the next several days.
Based on the results of your scans, your doctor will determine whether or not to give the second step of tositumomab treatment. In the second step, you will again receive the two injections.
The 2-step tositumomab treatment is usually given only once.
After you are treated with tositumomab, your body will retain radioactive material for several days. During this time you will be giving off a small amount of radiation to others around you. Your caregivers should give you instructions about how to avoid exposing other people to radiation until this effect wears off.
Tositumomab can lower blood cells that help your body fight infections and help your blood to clot. This can make it easier for you to bleed from an injury or get sick from being around others who are ill. Your blood will need to be tested every 3 months during treatment and possibly for a short time after you stop receiving this medicine.
While you are being treated with tositumomab, wash your hands often to prevent infections.
Tositumomab can increase your risk of developing hypothyroidism (underactive thyroid). You will be given other medications to protect your thyroid gland and to help prevent allergic reactions. You may need to keep taking some of these medications after your treatment ends.
Take all medications your doctor prescribes to help protect your thyroid gland. You may need to have blood tests to check your thyroid function at regular intervals for the rest of your life. Visit your doctor regularly.
This medication can cause unusual results with certain medical tests. You may also have an allergic reaction to diagnostic tests or treatments using mouse proteins or monoclonal antibodies. Tell any doctor who treats you that you have been treated with tositumomab.
What happens if I miss a dose?
Call your doctor for instructions if you miss an appointment for your tositumomab injection.
What happens if I overdose?
Since this medication is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.
What should I avoid after receiving tositumomab?
This medicine can pass into body fluids (urine, feces, vomit). For at least 48 hours after you receive a dose, avoid allowing your body fluids to come into contact with your hands or other surfaces. Avoid handling any of your body fluids without wearing latex rubber gloves. If another person is handling your fluids, they should wear gloves, eye protection, and a mask to cover the nose and mouth. Body fluids should not be handled by a woman who is pregnant or who may become pregnant.
When cleaning any spills of bodily fluid, use only disposable cleaning cloths that can be flushed down a toilet. Ask your doctor or health department how to dispose of any bodily fluid spills that cannot be flushed down a toilet.
To protect others from exposure to the radioactive matter in your body, try to stay at least 6 feet away from other people, especially children or pregnant women. Follow these steps for several days after your tositumomab treatment ends:
Avoid crowds and public places. Avoid traveling on long trips.
Do not share a bed or bathroom with another person.
Sit on the toilet while urinating and flush 3 times with the lid down after use.
Always wash your hands after using the bathroom.
Do not share a towel, wash cloth, or toothbrush with another person.
Do not share drinking glasses, plates, or silverware.
Wait at least 1 week before washing any of the clothing and bed or bath linens you have used during the week after your treatment. Keep these items separate from the laundry of other people in your home.
Wash your clothing and other items separately from other laundry in your home.
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 tositumomab. 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.
Avoid activities that may increase your risk of bleeding or injury. Use extra care to prevent bleeding while shaving or brushing your teeth.
Tositumomab side effects
Serious and sometimes fatal allergic reactions may occur during treatment with tositumomab. Tell your caregiver right away if you feel dizzy, nauseated, light-headed, sweaty, or have a fever, chills, chest tightness, wheezing, or trouble breathing. These effects can occur during the injection or up to 48 hours later.
Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
pale skin, feeling light-headed or short of breath, rapid heart rate, trouble concentrating;
easy bruising, unusual bleeding (nose, mouth, vagina, or rectum), purple or red pinpoint spots under your skin;
weakness, tired feeling, fever, chills, sore throat, body aches, flu symptoms;
blood in your urine or stools, coughing up blood or vomit that looks like coffee grounds; or
stabbing chest pain, wheezing, cough with yellow or green mucus; feeling short of breath.
Common side effects may include:
nausea, vomiting, diarrhea, stomach pain, loss of appetite;
joint or muscle pain;
mild itching or rash.
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.
See also: Side effects (in more detail)
Tositumomab dosing information
Usual Adult Dose for non-Hodgkin's Lymphoma:
Dosimetric dose : Tositumomab 450 mg IV infusion over 60 minutes followed by I-131 tositumomab 5 mCi I-131 and 35 mg protein IV infusion over 20 minutes
Therapeutic dose: Tositumomab 450 mg IV infusion over 60 minutes followed by I-131 tositumomab dose calculated to deliver 75 cGy total body irradiation for patients with normal platelet count (platelet count greater than 150,000/mm3 obtained within 28 days prior to dosing) 7 to 14 days after dosimetric step
-Do not administer the therapeutic dose if biodistribution is altered.
-See manufacturer's product information for instructions on assessing dosimetry and biodistribution and calculating the therapeutic dose.
What other drugs will affect tositumomab?
Other drugs may interact with tositumomab, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.
Where can I get more information?
- Your doctor or pharmacist can provide more information about tositumomab.
- Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
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