Interferon Beta-1a

Interferon beta-1a is a prescription medication that is used to treat multiple sclerosis. Interferon beta-1a belongs to a group of drugs called immunomodulators, which are thought to help limit the destruction of the protective myelin coating of nerve fibers.

Interferon beta-1a is a prescription medication used to treat relapsing forms of multiple sclerosis (MS). It will not cure MS but may decrease the number of flare ups and slow the occurrence of some of the disabilities that are common in people with MS. 

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Interferon Beta-1a may be found in some form under the following brand names:

• Avonex

• Rebif

Serious side effects of interferon beta-1a have been reported. See "Interferon beta-1a Drug Precautions" section.

Common side effects of interferon beta-1a include:

• headaches
• flu-like symptoms
• muscle pain, weakness
• nausea (upset stomach)
• general body pain
• fever 

This is not a complete list of interferon beta-1a side effects. Ask your doctor or pharmacist for more information.

Tell your doctor if you have any side effect that bothers you or that does not go away.

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

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

• acetaminophen (Tylenol)
• medicines for acquired immunodeficiency syndrome (AIDS) or human immunodeficiency virus (HIV)

This is not a complete list of interferon beta-1a drug interactions. Ask your doctor for more information.

Potential serious side effects include:

• Depression - Some people treated with interferons, including interferon beta-1a, have become depressed (feeling sad, feeling low or feeling bad about oneself). Some people have thought about killing themselves and a few have committed suicide. Depression is common in people with MS. If you are noticeably sadder or feeling more hopeless, you should tell a family member or friend right away and call your doctor as soon as possible. You should tell the doctor if you have ever had any mental illness, including depression, and if you take any medicines for depression.
• Liver problems - Your liver may be affected by using interferon beta-1a and a few patients have developed severe liver injury. Your healthcare provider may ask you to have regular blood tests to make sure that your liver is working properly. If your skin or the whites of your eyes become yellow or if you are bruising easily you should call your doctor immediately.
• Risk to pregnancy - If you become pregnant while using interferon beta-1a, you should stop using interferon beta-1a immediately and call your doctor. Interferon beta-1a may cause you to lose your baby (miscarry) or may cause harm to your unborn child. You and your doctor will need to decide whether the potential benefit of using interferon beta-1a is greater than the risks are to your unborn child.
• Allergic reactions - Some patients using interferon beta-1a have had severe allergic reactions leading to difficulty breathing. Allergic reactions can happen after your first dose or may not happen until after you have used interferon beta-1a many times. Less severe allergic reactions such as rash, itching, skin bumps or swelling of the mouth and tongue can also happen. If you think you are having an allergic reaction, stop using interferon beta-1a immediately and call your doctor.
• Blood problems - You may have a drop in the levels of infection-fighting blood cells, red blood cells or cells that help to form blood clots. If the drop in levels are severe, they can lessen your ability to fight infections, make you feel tired or sluggish or cause you to bruise or bleed easily.
• Seizures - Some patients have had seizures while using interferon beta-1a, including some patients who have never had seizures before. It is not known whether the seizures were related to the effects of their MS, to interferon beta-1a, or to a combination of both. If you have a seizure while using interferon beta-1a, you should stop using interferon beta-1a and call your doctor right away.
• Heart problems - While interferon beta-1a is not known to have direct effects on the heart, a few patients who did not have a history of heart problems developed heart muscle problems or congestive heart failure after using interferon beta-1a. Some of the symptoms of heart problems are swollen ankles, shortness of breath, decreased ability to exercise, fast heartbeat, tightness in chest, increased need to urinate at night, and not being able to lay flat in bed. If you develop these symptoms or any heart problems while using interferon beta-1a, you should call your doctor right away.

Do not use interferon beta-1a if you have had an allergic reaction to interferon beta. (Allergic reactions include difficulty breathing, itching, flushing or skin bumps spread widely over the body). Do not use the vial formulation of interferon beta-1a if you have a history of hypersensitivity to albumin (human).

Medicines can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of interferon beta-1a there are no specific foods that you must exclude from your diet when receiving this medication.

Before receiving interferon beta-1a, tell your doctor about all of your medical conditions including if you have, or have had:

• mental illness or had treatment in the past for any mental illness, including depression and suicidal behavior
• problems with your thyroid gland
• blood problems such as bleeding or bruising easily and anemia (low red blood cells) or low white blood cells
• seizures (epilepsy)
• heart problems
• liver disease
• autoimmune disease (psoriasis, lupus, rheumatoid arthritis)

You should also tell your doctor if you:

• drink alcohol
• are pregnant or are planning to become pregnant 
• are breastfeeding or plan to breastfeed

You should tell your doctor if you are taking any other prescription or nonprescription medicines, vitamins or mineral supplements, or herbal products.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Interferon beta-1a falls into category C. In animal studies, pregnant animals were given large doses of this medication and had some babies born with problems. No well-controlled studies have been done in humans.

It is not known if interferon beta-1a crosses into human milk. Because many medications can cross into human milk and because of the possibility for serious adverse reactions in nursing infants with use of this medication, a choice should be made whether to stop nursing or stop the use of this medication. Your doctor and you will decide if the benefits outweigh the risk of using interferon beta-1a.

INTRAMUSCULAR, ONCE-WEEKLY FORM

To get the most benefit from this medicine, it is important that you use interferon beta-1a exactly as your doctor tells you.

• This form of interferon beta-1a is given by injection into the muscle (intramuscular injection) once a week, on the same day (for example, every Monday right before bedtime).
• If you miss a dose, you should take your next dose as soon as you remember. You should continue your regular schedule the following week.
• Do not inject intramuscular interferon beta-1a on two consecutive days. Take only the dose your doctor has prescribed for you.
• Do not change your dose unless you are told to by your doctor. If you take more than your prescribed dose, call your healthcare provider right away. Your doctor may want to monitor you more closely. You should always follow your doctor's instructions and advice about how to take this medication.
• If your doctor feels that you, or a family member or friend, may give you the injections, then you and/or the other person should be instructed by your doctor or other healthcare provider in how to prepare and inject your dose of interferon beta-1a.
• Do not try to give yourself injections at home until you are sure that you (or the person who will be giving you the injections) fully understands and is comfortable with how to prepare and inject the product.
• Always use a new, unopened interferon beta-1a vial or prefilled syringe for each injection. Never reuse the vials or syringes. It is important to keep your work area, your hands, and your injection site clean to minimize risk of infection. You should wash your hands prior to handling the syringe.
• It is important that you change your injection site each week. Do not inject into an area of the body where the skin is irritated, reddened, bruised, infected or scarred in any way. Use the alcohol wipe to thoroughly clean the skin at the injection site you have chosen. Using a circular motion, and starting at the injection site and moving outward, clean the injection site with an alcohol wipe.
• Let the skin area dry before you inject the interferon beta-1a.

SUBCUTANEOUS, 3X/WEEK FORM

This form of interferon beta-1a is given by injection under the skin (subcutaneous injection) on the same three days a week (for example, Monday, Wednesday and Friday). Your injections should be at least 48 hours apart so it is best to take them the same time each day. Your doctor will tell you what dose to use, and may change the dose based on how your body responds. You should not change the dose without talking with your doctor.

If you miss a dose, you should take your next dose as soon as you remember or are able to take it, then skip the following day. Do not take doses on two consecutive days. You should return to your regular schedule the following week. If you accidentally take more than your prescribed dose, or take it on two consecutive days, call your doctor right away.

You should always follow your doctor's instructions and advice about how to take this medication. If your doctor feels that you, or a family member or friend may give you the injections then you and/or the other person should be trained by your doctor or health care provider in how to give an injection. Do not try to give yourself (or have another person give you) injections at home until you (or both of you) understand and are comfortable with how to prepare your dose and give the injections.

Always use a new, unopened, pre-filled syringe or autoinjector for each injection. Do not reuse pre-filled syringes or autoinjectors.

It is important that you change your injection site each time interferon beta-1a is injected. This will lessen the chance of your having a serious skin reaction at the spot where you inject it. You should always avoid injecting this medication into an area of skin that is sore, reddened, infected or otherwise damaged.

Use interferon beta-1a exactly as your doctor prescribes it.

Intramuscular Form - The usual dose is 30 mcg injected intramuscularly (into the muscle) once a week. Do not change your dose unless your doctor tells you to.

Subcutaneous Form - Dosages are started low and gradually increased to 22 mcg or 44 mcg injected subcutaneously three times per week.

If you have injected too much interferon beta-1a, seek medical emergency help or call your local Poison Control Center right away.

INTRAMUSCULAR FORM

Interferon beta-1a in prefilled syringes should be refrigerated (36-46°F or 2-8°C). Once removed from the refrigerator, interferon beta-1a in a prefilled syringe should be allowed to warm to room temperature (about 30 minutes). Do not use external heat sources such as hot water to warm interferon beta-1a in a prefilled syringe. Should refrigeration be unavailable, interferon beta-1a in a prefilled syringe can be stored up to 77°F (25°C) for a period up to 7 days. Once the product is removed from the refrigerator, it must not be stored above 77°F (25°C). If the product has been exposed to conditions other than those recommended, DISCARD THE PRODUCT, DO NOT USE and call your pharmacist. Do not expose to high temperatures. Do not freeze. Protect from light.

You must be certain that interferon beta-1a prefilled syringe is not exposed to temperatures above 77°F (25°C) If in doubt, DISCARD THE PRODUCT, DO NOT USE and call your pharmacist.

• When traveling, consider packing your interferon beta-1a prefilled syringe in a small cooler or insulated bag to help protect it from extreme temperatures. Be careful not to freeze.
• You should carry your interferon beta-1a prefilled syringe with you when flying, such as in your carry-on bag.
• Do not leave your interferon beta-1a prefilled syringes anywhere in your car when you are not in the car.
• Do not store interferon beta-1a in a location that may become hot, such as on a windowsill.

SUBCUTANEOUS FORM

Interferon beta-1a is packaged in pre-filled syringes with needles already attached to the syringe and in pre-assembled, single-use autoinjectors, called Rebidose, with needles already attached within the autoinjector.

Interferon beta-1a should be stored refrigerated between 36°F to 46°F (2°C to 8°C). Do Not Freeze. If a refrigerator is not available, it may be stored between 36°F to 77° °F (2°C to 25°C) for up to 30 days and away from heat and light.

Disposal of syringes and needles

There may be special state and/or local laws for disposing of used needles and syringes. Your doctor, nurse or pharmacist should provide you with instructions on how to dispose of your used needles and syringes.

• Always keep your disposal container out of the reach of children.
• DO NOT throw used needles and syringes into the household trash and DO NOT RECYCLE.