Interferon Beta-1A

What are other names for this medicine?

Type of medicine: antiviral; biological response modulator; immune system booster

Generic and brand names: interferon beta-1a, injection; Avonex; Rebif

What is this medicine used for?

This medicine is given by injection to treat relapsing forms of multiple sclerosis to slow the progression of the disease. This medicine may be used for other conditions as determined by your healthcare provider.

What should my healthcare provider know before I take this medicine?

Before taking this medicine, tell your healthcare provider if you have ever had:

• an allergic reaction to any medicine or to human albumin
• bleeding problems or blood disorders such as anemia
• depression or anxiety
• heart disease
• liver disease
• seizures
• thyroid disease

Females of childbearing age: Do not take this medicine if you are pregnant or plan to become pregnant. If you become pregnant while you are taking this medicine, contact your healthcare provider right away. Do not breast-feed while taking this medicine without discussing with your healthcare provider.

How do I use it?

Often you can give yourself these shots or have someone at home give them to you. Check the label on the medicine for directions about your specific dose. Be sure you know how and when to have them and how much medicine to use. Use sterile, disposable syringes and needles. Use them only once and dispose of them safely, following your healthcare provider's instructions.

If you are taking Rebif, it is usually given by injection under the skin (subcutaneous injection). Rebif comes in a prefilled syringe with needles already attached to the syringe. You may also choose to take the prefilled syringes in an autoinjection device which may make the injections easier. Talk with your healthcare provider about this. Rebif shots are given on the same 3 days a week (for example, on Monday, Wednesday, and Friday). Injections must be given at least 48 hours apart. It is best to give the shots at the same time of day, such late in the afternoon or evening, each time.

If you are taking Avonex, it is usually given once a week by injection (shots) into a muscle. Avonex comes in a powder single-use vial and a liquid in a prefilled syringe. The powder in the single-use vial must be mixed with sterile water before it is used.

Carefully read and follow the directions that come in the package of medicine for preparing the shots. Wash your hands before using the medicine.

If you are not sure of how to give yourself the shots, ask your healthcare provider or pharmacist for help.

Take this medicine exactly as your healthcare provider prescribes. Do not take more or less than prescribed. Do not stop taking this medicine without your healthcare provider's approval.

What if I miss a dose?

If you miss a dose or an appointment for a dose, take it as soon as possible or reschedule your appointment as soon as possible. Do not give 2 injections within 2 days of each other. If you accidentally take more than the prescribed dose or take it 2 days in a row, call your healthcare provider right away.

What if I overdose?

If you or anyone else has intentionally taken too much of this medicine, call 911 or go to the emergency room right away. If you pass out, have seizures, weakness or confusion, or have trouble breathing, call 911. If you think that you or anyone else may have taken too much of this medicine, call the poison control center. Do this even if there are no signs of discomfort or poisoning. The poison control center number is 800-222-1222.

Symptoms of an acute overdose may include: drowsiness, confusion, joint and muscle pain.

What should I watch out for?

If you feel depressed or have thoughts of suicide, contact your healthcare provider right away.

You may have mild fever, chills, and muscle aches when you first start taking this medicine. These side effects usually get better with time. Talk with your healthcare provider if the side effects are bothersome.

This medicine may cause serious liver problems. If you develop nausea, vomiting, a fever, abdominal pain, yellowing of your eyes or skin, or severe fatigue, contact your healthcare provider right away. These may be signs of liver damage. Alcohol may increase the risk of liver problems. Do not drink alcohol while taking this medicine unless your healthcare provider approves.

If you need emergency care, surgery, or dental work, tell the healthcare provider or dentist you are taking this medicine.

You may need regular lab tests to see how this medicine is affecting you. Keep all appointments for these tests.

What are the possible side effects?

Along with its needed effects, your medicine may cause some unwanted side effects. Some side effects may be very serious. Some side effects may go away as your body adjusts to the medicine. Tell your healthcare provider if you have any side effects that continue or get worse.

Life-threatening (Report these to your healthcare provider right away. If you cannot reach your healthcare provider right away, get emergency medical care or call 911 for help): Allergic reaction (hives; itching; rash; trouble breathing; tightness in your chest; swelling of your lips, tongue, and throat).

Serious (report these to your healthcare provider right away): Depression or thoughts of suicide, seizures, severe confusion, unusual bleeding or bruising, yellowing of the skin or eyes, dark yellow or brown urine, swelling of the fingers, ankles, or feet, sudden shortness of breath, fast heartbeat, chest pain.

Other: Headache, fever, chills, sweating, pain, infection, tiredness, muscle or joint pain, nausea, diarrhea, trouble sleeping, dizziness, weakness.

What products might interact with this medicine?

When you take this medicine with other medicines, it can change the way this or any of the other medicines work. Nonprescription medicines, vitamins, natural remedies, and certain foods may also interact. Using these products together might cause harmful side effects. Talk to your healthcare provider if you are taking:

• zidovudine (Retrovir)

Do not have any vaccinations with live virus vaccines unless your healthcare provider approves. Do not drink alcohol while taking this medicine.

Keep a list of all your medicines with you. List all the prescription medicines, nonprescription medicines, supplements, natural remedies, and vitamins that you take. Be sure that you tell all healthcare providers who treat you about all the products you are taking.

How should I store this medicine?

Keep this medicine refrigerated. Protect it from heat, high humidity, and bright light. Do not let it freeze. Use it as soon as possible after preparing the solution. Warm the medicine to room temperature (about 30 minutes) before injection.

This advisory includes selected information only and may not include all side effects of this medicine or interactions with other medicines. Ask your healthcare provider or pharmacist for more information or if you have any questions.

Ask your pharmacist for the best way to dispose of outdated medicine or medicine you have not used. Do not throw medicines in the trash.

Keep all medicines out of the reach of children.

Do not share medicines with other people.