See also Warning and How to Use section.
Nausea, vomiting, diarrhea, tiredness, swelling of hands/ankles/feet, or trouble sleeping may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
People using this medication may have serious side effects. However, you have been prescribed this drug because your doctor has judged that the benefit to you is greater than the risk of side effects. Careful monitoring by your doctor may decrease your risk.
This medication decreases bone marrow function, an effect that may lead to a low number of blood cells such as red cells, white cells, and platelets. This effect can cause anemia, decrease your body's ability to fight an infection, or cause easy bruising/bleeding. Your doctor will order blood tests to check for this side effect. It is important to keep all medical/lab test appointments. Tell your doctor right away if you develop any of the following symptoms: easy bruising/bleeding, pale skin, unusual tiredness, signs of infection (such as fever, chills, cough, persistent sore throat).
Ofatumumab sometimes causes side effects due to the rapid destruction of cancer cells (tumor lysis syndrome). To lower your risk, your doctor may add a medication and tell you to drink plenty of fluids. Tell your doctor right away if you have symptoms such as: low back/side pain (flank pain), signs of kidney problems (such as painful urination, pink/bloody urine, change in the amount of urine), muscle spasms/weakness.
A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.