Brand Name(s):

  • Avonex®

WHY is this medicine prescribed?

Interferon beta-1a is used to decrease the number of episodes of symptoms and slow the development of disability in patients with relapsing-remitting (symptoms come and go) multiple sclerosis (MS, a disease in which the nerves do not function properly and patients may experience weakness, numbness, loss of muscle coordination and problems with vision, speech, and bladder control). Interferon beta-1a has not been shown to help patients with chronic progressive (symptoms are almost always present and worsen over time) MS. Interferon beta-1a is in a class of medications called immunomodulators. It is not known how interferon beta-1a works to treat MS.

HOW should this medicine be used?

Interferon beta-1a intramuscular injection comes as a powder to be mixed into a solution for injection, and also as a prefilled injection syringe. This medication is injected into a muscle, usually once a week, on the same day each week. It is best to inject the medication at around the same time of day on your injection days, usually 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.

Interferon beta-1a controls the 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 in your doctor's office. After that, you can inject interferon beta-1a 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.

Your doctor or pharmacist will give you the manufacturer's patient information sheet (medication guide) when you begin treatment with interferon beta-1a 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 ( Web Site) to obtain the interferon beta-1a Medication Guide.

Always use a new, unopened vial or prefilled syringe and needle for each injection. Never reuse vials, syringes, or needles. Throw away used syringes and needles in a puncture-resistant container, kept out of reach of children. Talk to your doctor or pharmacist about how to throw away the puncture-resistant container.

You can inject interferon beta-1a in your upper arms or thighs. Use a different spot for each injection. 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 into an area where the skin is sore, red, bruised, scarred, infected, irritated, or abnormal in any way.

To prepare interferon beta-1a powder for injection, follow these steps:

  • Wash your hands well with antibacterial soap.
  • Remove the interferon beta-1a vial from the refrigerator. Allow it to warm to room temperature for about 30 minutes before using. Do not use a heat source such as hot water or a microwave to warm the vial.
  • Set up a clean, well-lit, flat work surface, like a table, to collect all the supplies you will need. Assemble these supplies: vial of interferon beta-1a, vial of sterile water, sterile syringe, sterile needle, blue MICRO PIN (vial access pin), alcohol wipes, and puncture-resistant container.
  • Check the expiration dates on the vials of interferon beta-1a powder and sterile water. If either vial is expired, do not use that vial and call your pharmacist.
  • Remove the caps from the vials of interferon beta-1a powder and sterile water. Clean the rubber stopper on the top of each vial with an alcohol wipe.
  • Remove the small light blue protective cover from the end of the syringe barrel with a counterclockwise (toward the left) turn.
  • Attach the blue MICRO PIN to the syringe by turning clockwise (toward the right) until it is tight. Do not overtighten.
  • Pull the MICRO PIN cover straight off, without twisting. Save the cover for later use.
  • Pull back the syringe plunger to the 1.1-mL mark on the syringe.
  • Firmly push the MICRO PIN on the syringe down through the center of the rubber stopper of the sterile water vial.
  • Push down on the plunger of the syringe until it cannot be pushed down any further.
  • Keep the MICRO PIN in the vial and turn the vial and syringe upside down.
  • Keep the MICRO PIN in the liquid while you slowly pull back on the syringe plunger to the 1.1-mL mark.
  • Gently tap the syringe with your finger to make any air bubbles rise to the top. If there are bubbles, slowly press the plunger in just enough to push the bubbles (but not liquid) out of the syringe. Make sure there is still 1.1 mL of sterile water in the syringe.
  • Slowly pull the MICRO PIN out of the sterile water vial.
  • Carefully push the MICRO PIN through the center of the rubber stopper of the interferon beta-1a powder vial. Pushing the MICRO PIN through the vial stopper off-center can cause the stopper to fall into the vial. If the stopper falls into the vial, do not use that vial. Get a new vial and continue to prepare your dose.
  • Slowly push down on the plunger until the syringe is empty. Do not aim the stream of water directly on the medication powder. A forceful or direct stream of liquid on the powder will cause foaming and make it difficult to withdraw the medication.
  • Without removing the syringe, gently swirl the vial until the interferon beta-1a powder is dissolved. Do not shake. The solution should be clear to slightly yellow and should not have any particles. Do not use the vial if the solution is cloudy, has particles in it, or is another color.
  • Turn the vial and syringe upside down. Slowly pull back on the plunger of the syringe until it is filled to the 1.0-mL mark. If bubbles appear, push the solution slowly back into the vial and try again.
  • Continue to hold the vial and syringe upside down. Tap the syringe gently to make any air bubbles rise to the top. Press the plunger in until the solution moves up to the top of the syringe and there is still 1.0 mL of solution left in the syringe. Pull the MICRO PIN out of the vial.
  • Hold the syringe upright and carefully replace the cover on the MICRO PIN. Then remove the MICRO PIN from the syringe with a counterclockwise (to the left) turn.
  • Attach the sterile needle for injection to the syringe by turning the needle clockwise (to the right) until it is tight.
  • Throw away the blue MICRO PIN in a puncture-resistant container. See below for injection instructions.

To prepare a prefilled syringe of interferon beta-1a intramuscular injection, follow these steps:

  • Wash your hands well with antibacterial soap. Set up a clean, well-lit, flat work surface, like a table, to collect all the supplies you will need. Remove the prefilled syringe from the refrigerator and allow it to warm to room temperature for about 30 minutes before using. Do not use a heat source such as hot water or a microwave to warm the syringe.
  • Check the syringe to be sure it is safe to use. The syringe should be labeled with the correct name of the medication and an expiration date that has not passed and should contain a clear, colorless solution filled to the 0.5-mL mark. Hold the syringe so that the rubber cap is facing down and the 0.5-mL mark on the syringe is at eye level. Check to make sure the lowest point of the curved surface of the liquid in the syringe is level with or very close to the 0.5-mL mark. If the syringe does not have the correct amount of liquid, the syringe is expired, or the solution is cloudy, discolored, or contains any particles, do not use the syringe and call your pharmacist.
  • Hold the prefilled syringe upright, with the rubber cap facing up.
  • Remove the rubber cap by turning and gently pulling the cap in a clockwise (toward the right) direction.
  • Open the needle package and attach the needle to the syringe by firmly pressing it onto the syringe and turning it a half-turn clockwise (toward the right). Be sure to attach the needle tightly so medication will not leak.

To inject an intramuscular dose of interferon beta-1a, follow these steps:

  • Use a new alcohol wipe to clean the skin in the spot where you will inject interferon beta-1a. Use a circular motion, starting at the injection spot and moving outward. Let the skin dry before you inject interferon beta-1a.
  • Pull the protective cover straight off the needle without twisting.
  • Use one hand to stretch the skin out around the spot where you will inject the medication. Use your other hand to hold the syringe like a pencil. Use a quick motion to stick the needle in the skin at a 90-degree angle (straight up and down) and push the needle through the skin and into your muscle.
  • If you are injecting your medication using a prefilled syringe, skip this step and go on to Step 5. If you are injecting your medication using a syringe that you filled yourself, let go of the skin and use that hand to gently pull back slightly on the syringe plunger. If you see blood come into the syringe, pull the needle out of the injection spot and put pressure on the spot with a gauze pad.You will need to replace the needle with a new needle, choose a new spot for injection, and go back to Step 1.
  • Hold the syringe with one hand and use the other hand to slowly push the plunger down until the syringe is empty.
  • Hold a gauze pad near the needle at the injection spot and pull the needle straight out of the skin. Use the gauze pad to apply pressure to the spot for a few seconds or rub gently in a circular motion.
  • If there is slight bleeding at the spot, wipe it off with the gauze pad, and apply an adhesive bandage if necessary.
  • Throw away the used syringe and needle in a puncture-resistant container.
  • After 2 hours, check the injection site for redness, swelling, or tenderness. If you have redness, swelling, or tenderness that does not go away in a few days or is severe, call your doctor.

Are there OTHER USES for this medicine?

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,

  • tell your doctor and pharmacist if you are allergic to interferon beta-1a, any other interferon product, any other medications, human albumin, natural rubber, latex, or any of the ingredients in interferon beta-1a intramuscular injection. Ask your pharmacist for a list of the ingredients in interferon beta-1a.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: acetaminophen (Tylenol, others); antidepressants; azathioprine (Imuran); cancer chemotherapy medications; cholesterol-lowering medications (statins);cyclosporine (Neoral, Sandimmune);iron products; isoniazid (INH, Nydrazid);medications for acquired immunodeficiency syndrome (AIDS) or human immunodeficiency virus (HIV);methotrexate (Rheumatrex); niacin (nicotinic acid);rifampin (Rifadin, Rimactane); salicylate pain relievers such as aspirin, choline magnesium trisalicylate, choline salicylate (Arthropan), diflunisal (Dolobid), magnesium salicylate (Doan's, others), and salsalate (Argesic, Disalcid, Salgesic); sirolimus (Rapamune); and tacrolimus (Prograf). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • tell your doctor if you drink or have ever drunk large amounts of alcohol and if you have or have ever had AIDS or HIV; an autoimmune disease other than MS (a disease in which the body attacks its own cells; ask your doctor if you are unsure if you have this type of disease); blood problems such as anemia (red blood cells that do not bring enough oxygen to all parts of the body), low white blood cells, or easy bruising or bleeding; cancer; anxiety,depression, other mood disorders, or mental illness; difficulty falling asleep or staying asleep; seizures; angina (recurring chest pain); or heart, liver, or thyroid disease.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while using interferon beta-1a, stop using the medication and call your doctor immediately. Interferon beta-1a may harm the fetus.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are using interferon beta-1a.
  • ask your doctor about the safe use of alcoholic beverages while you are using interferon beta-1a. Alcohol can increase the risk that you will develop serious side effects from interferon beta-1a.
  • you should know that you may have flu-like symptoms such as headache, fever, chills, sweating, muscle aches, nausea, vomiting, and tiredness that last for a day after your injection. Your doctor may tell you to inject your medication at bedtime and take an over-the-counter pain and fever medication to help with these symptoms. These symptoms usually lessen or go away over time. Talk to your doctor if these symptoms last longer than the first few months of therapy, or if they are difficult to manage or become severe.

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. Do not inject interferon beta-1a two days in a row. Do not inject a double dose to make up for a missed dose. 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 may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • tight muscles
  • dizziness
  • numbness, burning, tingling, or pain in hands or feet
  • joint pain
  • stomach pain
  • eye problems
  • runny nose
  • toothache
  • hair loss
  • bruising, pain, redness, swelling, bleeding, or irritation at the injection spot

Some side effects can be serious. The following symptoms are uncommon, but if you experience any of them, call your doctor immediately:

  • depression
  • thoughts of hurting or killing yourself
  • feeling very emotional
  • hallucinating (seeing things or hearing voices that do not exist)
  • seizures
  • unexplained weight gain or loss
  • feeling cold or hot all the time
  • trouble breathing when lying flat in bed
  • increased need to urinate during the night
  • painful or difficult urination
  • decreased ability to exercise
  • chest pain or tightness
  • fast or irregular heartbeat
  • pale skin
  • excessive tiredness
  • lack of energy
  • loss of appetite
  • unusual bleeding or bruising
  • pain or swelling in the upper right part of the stomach
  • yellowing of the skin or eyes
  • dark brown urine
  • light-colored bowel movements
  • sore throat, cough, or other signs of infection
  • hives
  • rash
  • itching
  • swelling of the face, throat, tongue, lips, eyes, hands, arms, feet, ankles, or lower legs
  • difficulty breathing or swallowing
  • hoarseness
  • flushing

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 [at Web Site] or by phone [1-800-332-1088].

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 interferon beta-1a prefilled syringes and vials in the refrigerator. Do not freeze interferon beta-1a, and do not expose the medication to high temperatures.If a refrigerator is not available, you can store the vials of interferon beta-1a at room temperature, away from heat and light, for up to 30 days. After you mix interferon beta-1a powder with sterile water, store it in the refrigerator and use it within 6 hours. Use prefilled syringes within 12 hours after you take them out of the refrigerator. Throw away mixed vials or syringes after this time has passed. Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

What should I do in case of OVERDOSE?

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

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.

Do not let anyone else use your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: February 11, 2012.