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What should I discuss with my health care provider before I receive tositumomab (Bexxar Dosimetric, BexxarTherapeutic)?
You should not receive this medication if you are allergic to mouse proteins, or if you have ever had an allergic reaction to a monoclonal antibody.
To make sure you can safely receive tositumomab, tell your doctor if you have any of these other conditions:
FDA pregnancy category X. 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 (Bexxar Dosimetric, BexxarTherapeutic)?
Tositumomab is injected into a vein through an IV. You will receive this injection in a clinic or hospital setting. Tositumomab treatment consists of two different injections (tositumomab, and iodine I-131 tositumomab). These injections must be given one at a time and injected slowly through an IV infusion. The first injection is given over at least 60 minutes and the second injection is given over at least 20 minutes.
Before and during your tositumomab treatment, 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 for up to 2 weeks after your treatment.
The tositumomab treatment is usually given in two steps over a span of 7 days. In the first treatment 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 the tositumomab injections are circulating throughout your body. You may receive at least 2 more scans over the next 6 or 7 days.
Based on the results of your scans, your doctor will determine whether or not to give the second step of tositumomab treatment, and how large your dose should be.
In step 2 of the treatment, you will again receive the two injections one at a time. These injections are considered your therapeutic dose. The 2-step tositumomab treatment is usually given only once, so you are not likely to receive a second course of treatment with this medication.
Tositumomab can lower blood cells that help your body fight infections. This can make it easier for you to bleed from an injury or get sick from being around others who are ill. Your blood may need to be tested often. Visit your doctor regularly.
Wash your hands often to prevent infections.
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 increase your risk of developing hypothyroidism (underactive thyroid). Hypothyroidism can be treated with daily thyroid replacement medication.
Take all medications your doctor prescribes to help protect your thyroid gland when you receive tositumomab. 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.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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