Skip to Content
UW Health SMPH
American Family Children's Hospital
DONATE Donate
SHARE TEXT

interferon beta-1a

Pronunciation: in ter FEAR on BAY ta

Brand: Avonex, Avonex Prefilled Syringe, Rebif

What is the most important information I should know about interferon beta-1a?

Multum nopreg

This medication may be harmful to an unborn baby, or may cause a miscarriage. Do not use interferon beta-1a if you are pregnant. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

Before using interferon beta-1a, tell your doctor if you are allergic to any drugs, or if you have liver disease, a thyroid disorder, epilepsy or other seizure disorder, heart disease, chest pain (angina), congestive heart failure, a heart rhythm disorder, or a history of depression or suicidal behavior.

Multum emt

Some patients using interferon medications have become very depressed or had thoughts of suicide. Stop using interferon beta-1a if you have symptoms of depression (sadness, crying, loss of interest in things you once liked) or if you have any thoughts of hurting yourself.

Multum donot

Do not self-inject this medicine if you do not fully understand how to give the injection and properly dispose of used needles and syringes.

To be sure this medication is not causing harmful effects, your blood may need to be tested often. Your liver or thyroid function may also need to be tested. Visit your doctor regularly.

What is interferon beta-1a?

Interferon beta-1a is made from human proteins. Interferons help the body fight viral infections.

Interferon beta-1a is used to treat relapsing multiple sclerosis (MS). This medication will not cure MS, it will only decrease the frequency of relapse symptoms.

Interferon beta-1a may also be used for other purposes not listed in this medication guide.

What should I discuss with my healthcare provider before using interferon beta-1a?

Multum donot

Do not use this medication if you are allergic to interferons or human albumin.

Multum emt

Some patients using interferon medications have become very depressed or had thoughts of suicide. Stop using interferon beta-1a if you have symptoms of depression (sadness, crying, loss of interest in things you once liked) or if you have any thoughts of hurting yourself.

If you have any of these other conditions, you may need a dose adjustment or special tests:

  • liver disease;
  • epilepsy or other seizure disorder;
  • heart disease, chest pain (angina), congestive heart failure, or a heart rhythm disorder;
  • a thyroid disorder; or
  • a history of depression or suicidal behavior.
Multum nopreg

FDA pregnancy category C. This medication may be harmful to an unborn baby, or may cause a miscarriage. Do not use interferon beta-1a if you are pregnant. Tell your doctor if you become pregnant during treatment.

Multum nobrfeed

It is not known whether interferon beta-1a passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

Avonex powder contains albumin, but the Avonex prefilled syringe does not. Albumin comes from human plasma (part of the blood) and may contain viruses and other infectious agents that can cause disease. Although donated human plasma is screened, tested, and treated to reduce the risk of it containing anything that could cause disease, there is still a small possibility it could transmit disease. Talk with your doctor about the risks and benefits of using this medication.

How should I use interferon beta-1a?

Avonex is injected into a muscle. It is usually given once weekly at bedtime, on the same day each week (such as every Monday). Follow your doctor's instructions.

Rebif is injected under the skin. It is usually given 3 times per week (such as Monday, Wednesday, and Friday) at the same time on each dosing day. Follow your doctor's instructions.

Multum donot

You may be shown how to use injections at home. Do not self-inject this medicine if you do not fully understand how to give the injection and properly dispose of used needles and syringes.

This medication comes with patient instructions for safe and effective use. Follow these directions carefully. Ask your doctor or pharmacist if you have any questions.

Use a different place on your body each time you give the injection. Your care provider will show you the best places on your body to inject the medication. Do not inject into the same place two times in a row.

The powder form of Avonex must be mixed with a liquid (diluent) in the medicine vial. Gently swirl but do not shake the vial after mixing the medicine. The mixture should be clear or light yellow. Do not use the mixture if it has changed colors or has any particles in it. Mix a new dose or call your doctor for a new prescription.

Multum donot

Do not draw your dose into a syringe until you are ready to give yourself an injection.

Each prefilled syringe or single use vial (bottle) of this medicine is for one use only. Throw away after one use, even if there is still some medicine left after injecting your dose.

Use each disposable needle only one time. Throw away used needles in a puncture-proof container (ask your pharmacist where you can get one and how to dispose of it). Keep this container out of the reach of children and pets.

Interferon beta-1 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. Your liver or thyroid function may also need to be tested. Visit your doctor regularly.

Multum refig

Store interferon beta-1a in a refrigerator. Do not freeze. You may take the Avonex prefilled syringe out of the refrigerator and allow it to reach room temperature before giving the injection. Do not heat the medicine before using.

Multum rt

Interferon beta-1a may be kept at room temperature for short periods if protected from light. Avonex powder or Rebif prefilled syringes can be stored at room temperature for up to 30 days. Avonex prefilled syringes can be stored at room temperature for only 7 days.

Multum refig

After mixing Avonex powder with a diluent, store in the refrigerator and use it within 6 hours.

Throw away any interferon beta-1a that has become frozen or has been exposed to light or high heat.

What happens if I miss a dose?

Call your doctor for instructions if you miss a dose of this medication. Your injections should be at least 48 hours apart. Do not use interferon beta-1a injections 2 days in a row.

What happens if I overdose?

Multum emt

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using interferon beta-1a?

Multum noalcohol

Avoid drinking alcohol. It may increase your risk of liver damage.

Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.

What are the possible side effects of interferon beta-1a?

Multum emt

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Multum donot

Call your doctor at once if you have a serious side effect such as:

  • depressed mood, anxiety, trouble sleeping, restlessness, or thoughts of suicide or hurting yourself;
  • easy bruising or bleeding, weakness;
  • seizure (convulsions);
  • numbness or tingling in your hands or feet;
  • pain or burning when you urinate;
  • pain, swelling, or skin changes where the injection was given;
  • fever, chills, body aches, flu symptoms; or
  • nausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Less serious side effects may include:

  • headache, dizziness;
  • stomach pain; or
  • runny or stuffy nose.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect interferon beta-1a?

Interferon beta-1a can harm your liver. This effect is increased when you also use other medicines harmful to the liver. Many other drugs (including some over-the-counter medicines) can be harmful to the liver, such as:

  • acetaminophen (Tylenol);
  • cancer medications;
  • tuberculosis medications;
  • birth control pills or hormone replacement therapy;
  • methotrexate (Rheumatrex, Trexall);
  • arthritis medications such as auranofin (Ridaura);
  • an antibiotic;
  • HIV/AIDS medications;
  • cholesterol medications such atorvastatin (Lipitor), simvastatin (Zocor), and others;
  • an ACE inhibitor such as benazepril (Lotensin), captopril (Capoten), lisinopril (Prinivil, Zestril), and others;
  • an NSAID (non-steroidal anti-inflammatory drug) such as ibuprofen (Motrin, Advil), naproxen (Aleve, Naprosyn), indomethacin (Indocin), and others; or
  • seizure medications such as carbamazepine (Carbatrol, Tegretol), phenytoin (Dilantin), or valproic acid (Depakene).

This list is not complete and other drugs may interact with interferon beta-1a. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.

Where can I get more information?

Your doctor or pharmacist can provide more information about interferon beta-1a.


Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2013 Cerner Multum, Inc. Version: 5.02. Revision date: 12/15/2010.

Your use of the content provided in this service indicates that you have read, understood and agree to the End-User License Agreement, which can be accessed by clicking on this link.

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.

Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.