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Interferon beta-1a

Pronunciation: in-ter-feer-on beta-one-â
Generic name: interferon beta-1a
Brand names: Avonex, Avonex Pen, Avonex Prefilled Syringe, Rebif, Rebif Rebidose
Dosage form: intramuscular injection, subcutaneous injection
Drug class: Interferons

Medically reviewed by Carmen Pope, BPharm. Last updated on Nov 26, 2024.

What is interferon beta-1a?

Interferon beta-1a (brand names Avonex, Rebif) is used to treat relapsing forms of multiple sclerosis (MS), including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults.

Interferon beta 1-a’s mechanism of action resembles that of interferons which are proteins naturally produced by our immune system that help regulate the body’s immune response and fight viral infections. Interferon beta 1-a is a man-made form of interferon that works in the same way, binding to specific receptors on cell surfaces and decreasing the activity of immune cells that attack the myelin sheath, reducing inflammation in the central nervous system, and helping to suppress the autoimmune response that characterizes MS. Interferon beta-1a belongs to the drug class called interferons. It may also be called an immunomodulator.

Interferon beta-1a will not cure MS, it will only decrease the frequency of relapse symptoms.

Interferon beta-1a first gained FDA approval on May 17, 1996, under the brand name Avonex. Rebif is another brand of interferon beta-1a that gained FDA approval on March 7, 2002. There is no interferon beta-1a generic.

Interferon beta-1a side effects

The most common side effects of Interferon beta 1-a include:

Serious side effects and warnings

Interferon beta 1-a can cause the following serious side effects. 

Behavioral health problems including depression and suicidal thoughts. You may have mood problems including:

Interferon beta 1-a may cause serious allergic and skin reactions. Symptoms may include:

Injection site problems. Interferon beta 1-a may cause redness, pain, itching, or swelling at the place where your injection was given. Call your healthcare provider immediately if an injection site becomes swollen and painful or the area looks infected. You may have a skin infection or an area of severe skin damage (necrosis) requiring treatment by a healthcare provider.

Blood problems. Interferon beta 1-a can affect your bone marrow and cause low red and white blood cell, and platelet counts. In some people, these blood cell counts may fall to dangerously low levels. If your blood cell counts become very low, you can get infections and problems with bleeding and bruising. Your healthcare provider may ask you to have regular blood tests to check for blood problems.

Heart problems, including heart failure. Some people who did not have a history of heart problems
developed heart muscle problems or congestive heart failure after receiving interferon beta 1-a. If you already have heart failure, interferon beta 1-a may cause your heart failure to get worse. Call your healthcare provider right away if you have worsening symptoms of heart failure such as shortness of breath or swelling of your lower legs or feet while using interferon beta 1-a. Some people using interferon beta 1-a may have other heart problems including:

Pulmonary arterial hypertension. Pulmonary arterial hypertension (high blood pressure in the arteries of the lungs) can occur with interferon beta products, including interferon beta 1-a. Symptoms may include new fatigue or shortness of breath. Contact your healthcare provider right away if you develop these symptoms.

Thrombotic microangiopathy (TMA). TMA is a condition that involves injury to the smallest blood vessels in your body. TMA can also cause injury to your red blood cells (the cells that carry oxygen to your organs and tissues) and your platelets (cells that help your blood clot) and can sometimes lead to death. Your healthcare provider may tell you to stop taking interferon beta 1-a if you develop TMA.

Seizures. Some people have had seizures while taking interferon beta 1-a.

Autoimmune diseases. Problems with easy bleeding or bruising (idiopathic thrombocytopenia), thyroid gland problems (hyperthyroidism and hypothyroidism), and autoimmune hepatitis have happened in some people who use interferon beta 1-a.

During your treatment with interferon beta 1-a see your healthcare provider regularly and have regular blood tests to check for side effects.

Tell your healthcare provider if you have any side effect that bothers you or that does not go away. These are not all the possible side effects of Interferon beta 1-a. For more information, ask your healthcare provider or pharmacist. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Before taking

Do not take interferon beta 1-a if you are allergic to interferon beta, human albumin, Rebif, Avonex, or any of the inactive ingredients in the injection.

Before you take interferon beta 1-a, tell your healthcare provider if you have or have had any of the following conditions:

Pregnancy

It is not known if interferon beta 1-a can harm your unborn baby.

Breastfeeding

Interferon beta 1-a may pass into your breastmilk. Talk with your healthcare provider about the best way to feed your baby if you take interferon beta 1-a.

How should I use interferon beta 1-a?

See the Instructions for Use that come with your interferon beta 1a product.

Avonex for intramuscular use

Interferon beta 1-a (Avonex brand) is given 1 time each week by injection into the muscle (intramuscular injection).

Change (rotate) the injection site you choose with each injection. This will help decrease the chance that you will have an injection site reaction.

Avonex comes as a:

After 2 hours, check your injection site for redness, swelling, or tenderness. If you have a skin reaction that does not clear up in a few days, contact your healthcare provider.

Your healthcare provider will decide which one is best for you.

Always use a new, unopened Avonex single-dose prefilled syringe or single-dose prefilled autoinjector pen for each intramuscular injection.

See the Avonex Package Insert for complete administration instructions.

Rebif for subcutaneous use

Interferon beta 1-a (Rebif brand) is given by injection under the skin (subcutaneous injection) on the same 3 days a week, for example, Monday, Wednesday, and Friday.

Your healthcare provider will tell you how much Interferon beta 1-a to inject and may change the dose based on how your body responds. Do not inject more than your healthcare provider tells you to.

Rebif comes as a:

Your healthcare provider will decide which is best for you. Always use a new, unopened, prefilled syringe or autoinjector for each injection. Do not reuse prefilled syringes or autoinjectors.

See the Rebif Package Insert for complete administration instructions.

Interferon beta 1a dosage

Avonex for intramuscular use

The recommended dose of Avonex for MS is Avonex 30 micrograms once a week.

See the Avonex Prescribing Information for full dosage instructions.

Perform the first injection under the supervision of an appropriately qualified healthcare professional.

Analgesics and/or antipyretics on treatment days may help ameliorate flu-like symptoms from the injection.

Rebif for subcutaneous injection

The recommended dose of Rebif for MS is either 22 mcg or 44 mcg injected subcutaneously three times per week.

Titration: Generally, the starting dose should be 20% of the prescribed dose three times per week, and increased over 4 weeks to the targeted recommended dose of either 22 mcg or 44 mcg injected subcutaneously three times per week.

Analgesics and/or antipyretics on treatment days may help ameliorate flu-like symptoms.

See the Rebif Prescribing Information for full dosage instructions.

What other drugs will affect interferon beta 1-a?

Tell your healthcare provider about all medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Interferon beta 1-a and other medicines may affect each other causing side effects. Ask your healthcare provider or pharmacist for a list of these medicines, if you are not sure.

Know the medicines you take. Keep a list of them to show your healthcare provider and pharmacist when you get a new medicine.

Does interferon beta-1a interact with my other drugs?

Enter medications to view a detailed interaction report using our Drug Interaction Checker.

Storage

Store interferon beta 1-a in the refrigerator between 36°F to 46°F (2°C to 8°C).

Do not freeze interferon beta 1-a.

If you cannot refrigerate your Rebif pen or autoinjector, you can store it at temperatures above 36°F and below 77°F (2°C to 25°C) for up to 30 days.

If you cannot refrigerate your Avonex pen or prefilled syringes you can store them at room temperature up to 77°F (25°C) for up to 7 days.

Keep interferon beta 1-a away from heat and light.

Ingredients

Avonex injection for intramuscular use ingredients

Active ingredient: interferon beta-1a

Inactive ingredients:

Rebif injection for subcutaneous use ingredients

Active ingredient: interferon beta-1a

Inactive ingredients: albumin (human), mannitol, sodium acetate, water for injection

Single-dose Rebif prefilled syringe is available as 8.8 mcg in 0.2 mL, and 22 mcg or 44 mcg in 0.5 mL.

Single-dose Rebif autoinjector is available as 8.8 mcg in 0.2 mL, and 22 mcg or 44 mcg in 0.5 mL.

Who makes interferon beta-1a?

Biogen Inc. makes interferon beta-1a under the brand name Avonex.

EMD Serono Inc. makes interferon beta-1a under the brand name Rebif.

Interferon beta-1a Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There are 2 for interferon beta-1a.

Avonex (interferon beta-1a) - Biogen Inc.
Formulation type Strength
Autoinjector 30 mcg/0.5 mL
Pre-Filled Syringe 30 mcg/0.5 mL
Single-Dose Vial 30 mcg Discontinued

View Avonex information in detail.

Rebif (interferon beta-1a) - EMD Serono, Inc.
Formulation type Strength
Autoinjector 22 mcg/0.5 mL
Autoinjector 44 mcg/0.5 mL
Autoinjector 8.8 mcg/0.2 mL
Pre-Filled Syringe 22 mcg/0.5 mL
Pre-Filled Syringe 44 mcg/0.5 mL
Pre-Filled Syringe 8.8 mcg/0.2 mL

View Rebif information in detail.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.