WHY is this medicine prescribed?
Interferon beta-1a subcutaneous injection is used to treat adults with various forms 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) including:
Interferon beta-1a is in a class of medications called immunomodulators. It works by decreasing inflammation and preventing nerve damage that may cause symptoms of multiple sclerosis.
HOW should this medicine be used?
Interferon beta-1a subcutaneous injection comes as a solution (liquid) in a prefilled syringe or a prefilled automatic injection device to inject subcutaneously (under the skin). It is usually injected three times a week. You should inject this medication on the same 3 days every week, for example, every Monday, Wednesday, and Friday. The injections should be spaced at least 48 hours apart, so it is best to inject your medication around the same time of day on each of your injection days. The best time to inject this medication is in the late afternoon or evening. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Use interferon beta-1a exactly as directed. Do not use more or less of it or use it more often than prescribed by your doctor.
Your doctor may start you on a low dose of interferon beta-1a and gradually increase your dose, not more than once every 2 weeks.
Interferon beta-1a controls symptoms of MS but does not cure it. Continue to use interferon beta-1a even if you feel well. Do not stop using interferon beta-1a without talking to your doctor.
You will receive your first dose of interferon beta-1a subcutaneous in your doctor's office. After that, you can inject interferon beta-1a subcutaneous yourself or have a friend or relative perform the injections. Ask your doctor or pharmacist to show you or the person who will be injecting the medication how to inject it. Before you use interferon beta-1a subcutaneous for the first time, your or the person who will be giving the injections should also read the manufacturer's information for the patient that comes with it. Follow the directions carefully.
Use a new prefilled syringe or prefilled automatic injection device each time you inject your medication. Do not reuse or share syringes or automatic injection devices. Even if there is still some solution left in the syringe or device after you inject, do not inject again. Discard used syringes or automatic injection devices in a puncture resistant container that is out of the reach of children. Talk to your doctor or pharmacist about how to discard the puncture-resistant container.
Always look at the medication in your prefilled syringe or automatic injection device before you use it. It should be a clear to slightly yellow solution. If the solution is cloudy, discolored, or contains particles or if the expiration date marked on the syringe or automatic injection device has passed, do not use that syringe or device.
Talk to your doctor or pharmacist about where on your body you should inject interferon beta-1a subcutaneous. You can inject interferon beta-1a in areas of your body with a layer of fat between the skin and muscle, such as your thigh, the outer surface of your upper arms, your stomach, or your buttocks. If you are very thin, only inject in your thigh or the outer surface of your arm for injection. Choose a different spot each time you inject your medication. Keep a record of the date and spot of each injection. Do not use the same spot two times in a row. Do not inject near your navel (belly button) or waistline or into an area where the skin is sore, red, bruised, scarred, infected, or abnormal in any way.
Your doctor or pharmacist will give you the manufacturer's patient information sheet (Medication Guide) when you begin treatment with interferon beta-1a subcutaneous injection and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website (http://www.fda.gov/Drugs/DrugSafety/ucm085729.htm) or the manufacturer's website to obtain the Medication Guide.
Are there OTHER USES for this medication?
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
What SPECIAL PRECAUTIONS should I follow?
Before using interferon beta-1a,
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?
Inject the missed dose as soon as you remember it. If you are scheduled for a dose the following day, skip that dose. Do not inject interferon beta-1a subcutaneous 2 days in a row. Do not inject a double dose to make up for a missed dose. You should return to your regular dosing schedule the following week. Call your doctor if you miss a dose and have questions about what to do.
What SIDE EFFECTS can this medicine cause?
Interferon beta-1a subcutaneous 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 call your doctor immediately or get emergency medical treatment:
Interferon beta-1a may cause other side effects. Call your doctor if you have any unusual problems while using 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, but do not freeze it. If a refrigerator is not available, you can store the medication at room temperature away from heat and light for up to 30 days.
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. Your doctor will order certain lab tests to check your body's response to interferon beta-1a subcutaneous injection.
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: September 15, 2023.