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Interferon beta-1a (Intramuscular, Subcutaneous)

Generic name: interferon beta-1a [ in-ter-FEER-on-BAY-ta-1a ]
Brand names: Avonex, Avonex Pen, Rebif, Rebif Rebidose, Rebif Rebidose Titration Pack
Drug class: Interferons

Medically reviewed by Drugs.com. Last updated on Feb 28, 2024.

Uses for interferon beta-1a

Interferon beta-1a injection is used to treat the relapsing forms of multiple sclerosis (MS), including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease. This medicine will not cure MS, but it may slow some of the disabling effects and decrease the number of relapses of the disease. Interferons are natural substances that are produced in the body to help fight infections. Interferon beta-1a is a synthetic (man-made) version of these substances.

This medicine is available only with your doctor's prescription.

Before using interferon beta-1a

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of interferon beta-1a injection in the pediatric population. Safety and efficacy have not been established.

Geriatric

Although appropriate studies on the relationship of age to the effects of interferon beta-1a injection have not been performed in the geriatric population, geriatric-specific problems are not expected to limit the usefulness of interferon beta-1a injection in the elderly. However, elderly patients are more likely to have age-related kidney, liver, or heart problems, which may require caution in patients receiving interferon beta-1a injection.

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

Proper use of interferon beta-1a

A nurse or other trained health professional will give you this medicine. You may also be taught how to give your medicine at home. This medicine is given as a shot under your skin (usually in the stomach, back of the upper arm, buttocks, or thighs) or into a muscle (usually in the thigh). A nurse or other trained health professional should watch the first Avonex® injection you give yourself.

If you are injecting interferon beta-1a yourself, use it exactly as directed by your doctor. Do not change your dose or dosing schedule without checking first with your doctor. The exact amount of medicine you need has been carefully worked out. Using too much will increase the risk for side effects, while using too little may not improve your condition.

You will be shown the body areas where this shot can be given. Use a different body area each time you give yourself a shot. Keep track of where you give each shot to make sure you rotate body areas. Do not inject into skin areas that are irritated, reddened, bruised, infected, or scarred in any way.

Check the injection site after 2 hours for redness, swelling, and tenderness.

Use only the brand of this medicine that your doctor prescribed. Different brands may not work the same way.

Rebif® comes as an autoinjector or a prefilled syringe. It works best if you use it at the same time (usually in the late afternoon or evening) on the same 3 days (eg, Monday, Wednesday, and Friday) at least 48 hours apart each week.

Avonex® comes as a prefilled autoinjector pen or a prefilled syringe.

Use a new needle or syringe each time you inject your medicine. Do not use any other needle for the prefilled autoinjector pen.

Each package of medicine contains a Medication Guide and a sheet called Instructions for Use. Read this information carefully and make sure you understand:

Allow Avonex® prefilled autoinjector pens and prefilled syringes and Rebif® autoinjector to warm to room temperature before injection by removing from the refrigerator for about 30 minutes. Do not heat them in a microwave oven or in hot water.

You may also receive other medicines (fever medicine, pain medicine) to help prevent or lessen flu-like symptoms (eg, fever, cough, chills, body aches) that may occur during treatment with this medicine.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Avonex®: If you miss a dose, give it as soon as you can. Go back to your regular schedule the following week. Do not use this medicine 2 days in a row.

Rebif®: If you miss a dose, give it as soon as you can. Skip the next day and give your regular dose 48 hours later. Go back to your regular schedule the following week. Do not use this medicine 2 days in a row.

Storage

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Store in the refrigerator. Do not freeze.

Store prefilled autoinjector pens or prefilled syringes in the refrigerator. Do not freeze. If refrigeration is not available, Rebif® prefilled syringes may be kept for up to 30 days at room temperature, away from heat (temperatures above 77 degrees F) and direct light. Avonex® prefilled autoinjector pens and prefilled syringes may be stored for up to 7 days at room temperature, away from heat (temperatures above 77 degrees F) and direct light.

Put the used needles into a hard, closed container that the needles cannot poke through. Keep this container away from children and pets.

Detailed Interferon beta-1a dosage information

Precautions while using interferon beta-1a

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.

This medicine may cause some people to be anxious, irritable, or display other abnormal behaviors. It may also cause some people to have suicidal thoughts and tendencies or to become more depressed. If you or your caregiver notice any of these side effects, tell your doctor right away.

Check with your doctor right away if you have dark urine, persistent loss of appetite, flu-like symptoms, headache, continuing vomiting, general feeling of tiredness or weakness, light-colored stools, right upper stomach pain or tenderness, or yellow eyes or skin. These could be symptoms of a serious liver problem.

This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and requires immediate medical attention. Call your doctor right away if you have a rash, itching, hoarseness, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth while you are using this medicine.

This medicine may lower the number of white blood cells in the blood. This will increase your chance of getting an infection. It can also lower the number of platelets in the blood. Platelets are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:

This medicine may cause redness, pain, or swelling at the injection site. Some patients have developed serious skin infection or damage (necrosis), including a permanent depression under the skin at the injection site. Contact your doctor right away if you notice depressed or indented skin, blue-green to black skin discoloration, or pain, redness, or sloughing (peeling) of the skin.

This medicine commonly causes a flu-like reaction, with aching muscles, chills, fever, headaches, joint pain, and nausea. Using your shot at bedtime may allow you to sleep through the symptoms. Your doctor may want you to take a medicine to help control the pain or fever (eg, acetaminophen or ibuprofen). Carefully follow your doctor's instructions about how to prevent or treat these symptoms.

Thrombotic microangiopathy, including thrombotic thrombocytopenic purpura and hemolytic uremic syndrome may occur while you are using this medicine. Tell your doctor right away if you have black, tarry stools, blood in the urine, difficulty with speaking, fever, pinpoint red spots on the skin, seizures, stomach pain, unusual bleeding or bruising, or yellow eyes or skin.

This medicine may cause pulmonary arterial hypertension (high blood pressure in the lungs). Check with your doctor right away if you have trouble breathing or unusual tiredness or weakness.

This medicine contains albumin, which comes from human blood. Some human blood products have transmitted certain viruses to people who have received them, although the risk is low. Human donors and donated blood are both tested for viruses to keep the transmission risk low. Talk with your doctor about this risk if you are concerned. The Avonex® prefilled autoinjector pen and prefilled syringe do not contain albumin which comes from donated human blood.

The tip cap of the Avonex® prefilled syringe contains dry natural rubber (a derivative of latex), which may cause allergic reactions in people who are sensitive to latex. Tell your doctor if you have a latex allergy before you start using this medicine.

Side Effects of interferon beta-1a

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Less common

Rare

Incidence not known

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Interferon beta-1a side effects (more detail)

Commonly used brand name(s)

In the U.S.

Available Dosage Forms:

Therapeutic Class: Immunological Agent

Pharmacologic Class: Interferon, Beta (class)

Further information

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

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