Precautions and Warnings With Tositumomab

• An infection or easily get infections
• Plans to receive a vaccination
• Thyroid problems
• A history of a negative reaction to a mouse protein
• Kidney disease, such as kidney failure (renal failure)
• Any allergies, including to foods, dyes, or preservatives.

• Pregnant or thinking of becoming pregnant
• Breastfeeding.

• Tositumomab can cause potentially serious infusion reactions. In some cases, these reactions have caused death. You will be given certain "premedication" by mouth before your tositumomab dose to help reduce your risk for these reactions. Contact your healthcare provider immediately if you experience symptoms of an infusion reaction, which may include:

• Fever and chills
• Low blood pressure, which could cause dizziness
• Unexplained swelling, especially of the mouth, lips, or throat
• Wheezing
• Shortness of breath
• Difficulty breathing or swallowing
• Sweating
• Stiffness
• Nausea.

• The majority of people who receive tositumomab will develop low blood cell counts. This can cause potentially serious or life-threatening problems, such as infections, anemia, or bleeding. Your healthcare provider will monitor your blood counts for up to 12 weeks after your last dose. If your blood cell counts become too low, you may need a blood transfusion or medicine to help your blood counts return to normal.
  

Contact your healthcare provider right away if you believe you have an infection, or if you notice any of the following problems:

• Unusual bleeding or bruising
• Paleness
• Weakness
• Fatigue
• Small reddish or purplish spots on the skin.

• There have been reports of people developing other forms of cancer, including leukemia and skin cancer, after receiving tositumomab. These cancers may develop years after tositumomab treatment ends. It is unknown whether this medicine is associated with causing other cancers.

• Tositumomab can cause hypothyroidism (an underactive thyroid gland). Therefore, you will need to take thyroid-protecting medicine starting 24 hours before your first tositumomab dose and continuing for two weeks after your last dose. You will need to have your thyroid function tested every year after you receive tositumomab.

• You could develop an allergy to mouse protein after receiving this medicine. This is called human anti-murine antibody (HAMA). HAMA increases the chance of an allergic reaction the next time you receive a medicine with mouse protein. It can also interfere with certain laboratory test results. Therefore, make sure to tell all of your healthcare providers that you have been treated with tositumomab.

• This medicine is linked with a radioactive element. Your body will give off radiation for several days after each dose. You should avoid close contact with other people for one to two weeks after treatment. Your healthcare provider will give you more information on how much contact you can safely have with other people during this time.

• It is unknown whether this medicine is safe for use in people with kidney disease.

• Talk to your healthcare provider before getting any type of vaccination or immunization during tositumomab treatment, or after you receive this medicine. The vaccines may be less effective. Also, you could become infected with the bacteria or viruses used to make "live" vaccines (see Drug Interactions With Tositumomab).

• Tositumomab may react with several other medications (see Drug Interactions With Tositumomab).

• This product is a pregnancy Category X medication, which means it can harm an unborn child if used during pregnancy (see Bexxar and Pregnancy).

• This medication is expected to pass through human milk. Therefore, if you are breastfeeding or plan to start, discuss this with your healthcare provider prior to receiving the drug (see Bexxar and Breastfeeding).