WHY is this medicine prescribed?
Ofatumumab injection is used for treatment of certain types of multiple sclerosis (MS; a disease in which the nerves do not function properly and people may experience weakness, numbness, loss of muscle coordination, and problems with vision, speech, and bladder control). Ofatumumab is in a class of medications called monoclonal antibodies. It works by stopping certain cells of the immune system from reaching the brain and spinal cord and causing damage.
HOW should this medicine be used?
Ofatumumab injection comes as a solution (liquid) in a prefilled dosing pen and a prefilled syringe to inject subcutaneously (under the skin) into your stomach, thigh, or upper arm. Inject once a week for the first 3 doses and then once monthly starting at week 4 of treatment for as long as your doctor recommends that you receive treatment.
Use ofatumumab injection exactly as directed. Do not inject more or less of it or inject it more often than prescribed by your doctor.
You will receive your first subcutaneous dose of ofatumumab injection in your doctor's office. After that, your doctor may allow you to inject ofatumumab or have a caregiver perform the injections. Before you use ofatumumab injection yourself the first time, read the written instructions that come with it. Ask your doctor or pharmacist to show you or the person who will be injecting the medication how to inject it.
Inject ofatumumab into the thigh or stomach area, except the area 2 inches (5 centimeters) around your navel. If a caregiver is giving you the injection, that person can also inject the medication into your upper arms. Use a different site for each injection. Do not inject into an area where the skin is tender, bruised, red, or hard or where you have scars, moles, or stretch marks.
Remove the prefilled dosing pens or prefilled syringes from the refrigerator 15 to 30 minutes before you are ready to inject the medication. Do not remove the needle cover from the prefilled syringe during this time. Check that the expiration date printed on the package has not passed. The liquid should be clear and colorless to slightly brownish-yellow and should not be cloudy or discolored or contain particles. Call your pharmacist if you notice any problems.
Do not shake the dosing pen or syringe. Be careful not to drop the medication onto a hard surface because this may damage the syringe or needle.
Never reuse or share dosing pens or syringes. Dispose of pens and syringes in a puncture-resistant container. Ask your doctor or pharmacist how to dispose of the puncture resistant container.
You may experience a reaction, usually within 24 hours after your injection. This reaction is most likely to occur after your first injection, but could happen at any time during your treatment. Call your doctor if you experience any of the following symptoms during or after your injection: bruising, pain, redness, swelling, or tenderness at the injection site; fever; headache; muscle pain; chills; or tiredness.
Are there OTHER USES for this medication?
Ofatumumab is also used and available through a special access program for chronic lymphocytic leukemia (CLL).
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
What SPECIAL PRECAUTIONS should I follow?
Before receiving ofatumumab,
What SPECIAL DIETARY instructions should I follow?
Unless your doctor tells you otherwise, continue your normal diet.
What should I do IF I FORGET to take a dose?
If you miss a dose during the first 3 weeks of treatment, talk to your doctor. If you miss a monthly dose of ofatumumab injection, inject it as soon as possible and then continue giving your doses a month apart.
What SIDE EFFECTS can this medicine cause?
Ofatumumab may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
Some side effects can be serious. If you experience any of these symptoms or those in the SPECIAL PRECAUTIONS section, call your doctor immediately or get emergency medical treatment:
Ofatumumab 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).
What should I do in case of OVERDOSE?
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at http://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.
What should I know about STORAGE and DISPOSAL of this medication?
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it in the refrigerator and away from light until the time of use; do not freeze.
Keep all medication out of sight and reach of children as many containers are not child-resistant. Always lock safety caps. Place the medication in a safe location - one that is up and away and out of their sight and reach. http://www.upandaway.org
Dispose of unneeded medications in a way so that pets, children, and other people cannot take them. Do not flush this medication down the toilet. Use a medicine take-back program. Talk to your pharmacist about take-back programs in your community. Visit the FDA's Safe Disposal of Medicines website http://goo.gl/c4Rm4p for more information.
What OTHER INFORMATION should I know?
Keep all appointments with your doctor and the laboratory.
Do not let anyone else use your medication. Ask your pharmacist any questions you have about refilling your prescription.
Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.
This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.
The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.
AHFS® Patient Medication Information™ Copyright, 2025. The American Society of Health-System Pharmacists®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.
Selected Revisions: October 15, 2025.