How does this medication work? What will it do for me?
Interferon beta-1a belongs to the group of medications known as immunomodulators. It is a form of a protein that is naturally made by our body's cells to fight infections and tumours. Interferon beta-1a is used to treat relapsing forms of multiple sclerosis (MS). It is also used to treat people who have had a single event of MS symptoms, which are likely a first sign of multiple sclerosis. This medication can also be used to treat people with another type of MS known as secondary progressive MS (SPMS) who are still having relapses. For people who have SPMS, the medication can decrease the frequency of relapses and reduce brain lesions seen on MRI scans.
Multiple sclerosis (MS) is a chronic and disabling disease caused by the body's own defense system attacking and destroying the protective covering (myelin) surrounding nerve fibres. Interferon beta-1a works by slowing down the attack of the body's defense cells on the nerves.
Interferon beta-1a will not cure MS but may decrease the number and severity of flare-ups of the disease, slow the progression of disability, reduce the use of corticosteroid medications (which are often used by people with MS), reduce the number of hospitalizations, and decrease the number and volume of active brain lesions (damaged areas of the brain) seen on MRI scans.
This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.
Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are being given this medication, speak to your doctor. Do not stop using this medication without consulting your doctor.
Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to use this medication if their doctor has not prescribed it.
What form(s) does this medication come in?
Rebif® prefilled syringe
Each prefilled syringe with 0.5 mL of solution contains interferon beta-1a 22 µg. Nonmedicinal ingredients: mannitol, poloxamer-188, methionine, benzyl alcohol, and sodium acetate buffer. Preservative-free.
Each prefilled syringe with 0.5 mL of solution contains interferon beta-1a 44 µg. Nonmedicinal ingredients: mannitol, poloxamer-188, methionine, benzyl alcohol, and sodium acetate buffer. Preservative-free.
Rebif® multi-dose prefilled cartridge
66 µg/1.5 mL cartridge
Each prefilled cartridge designed to deliver 3 doses of interferon beta-1a 22 µg/0.5 mL contains interferon beta-1a 66 µg. Nonmedicinal ingredients: mannitol, poloxamer-188, methionine, benzyl alcohol, and sodium acetate buffer.
132 µg/1.5 mL cartridge
Each prefilled cartridge designed to deliver 3 doses of interferon beta-1a 44 µg/0.5 mL contains interferon beta-1a 132 µg. Nonmedicinal ingredients: mannitol, poloxamer-188, methionine, benzyl alcohol, and sodium acetate buffer.
How should I use this medication?
The recommended dose of interferon beta-1a for relapsing-remitting forms of multiple sclerosis (MS) is 44 µg injected under the skin 3 times per week. Your doctor may reduce this dose to 22 µg injected under the skin 3 times per week if you are experiencing unacceptable side effects.
The recommended dose of interferon beta-1a for a single clinical event of multiple sclerosis (MS) is 44 µg injected under the skin 3 times per week.
In order to reduce side effects when first starting treatment, it is recommended the dose be gradually increased as follows:
- 20% of the recommended dose during the first 2 weeks of treatment,
- 50% of the recommended dose during the third and fourth weeks of treatment, and
- the full dose from the fifth week onwards.
Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way you are using the medication without consulting your doctor.
Interferon beta-1a is used with the guidance and supervision of a doctor. Your doctor or nurse may ask you to inject the medication at home once they have instructed you and are certain that you won't have any problems with doing it at home. Do not attempt to prepare or inject this medication on your own until you completely understand how to mix and inject a dose.
It is important that this medication be used exactly as prescribed by your doctor. If you forget to take a dose, skip the missed dose and continue with your regular dosing schedule. Do not inject a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.
Interferon beta-1a should be stored in the refrigerator. If storing in the refrigerator, allow the medication to reach room temperature before injecting it. Alternatively, it may be stored for a limited period of time (up to 30 days) at room temperature.
Use a different injection site for each dose. You should avoid injecting this medication into an area of skin that is sore, red, infected, or otherwise damaged. If you are having difficulty giving yourself injections, talk to your health care provider.
Please refer to the package insert (the written instructions that come in the medication package) for complete instructions on using this medication. Always wash your hands before preparing the medication and after you have used it.
Protect this medication from light, moisture, freezing, and high temperatures. Keep this medication out of the reach of children.
Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.
Who should NOT take this medication?
Do not use this medication if you:
- are allergic to interferon beta-1a, any form of interferon beta, or any ingredients of the medication
- have worsening or uncontrolled liver disease
What side effects are possible with this medication?
Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.
The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.
The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.
Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.
- decreased appetite
- difficulty sleeping
- flu-like symptoms (e.g., fever, chills, sweating, muscle aches, tiredness)
- hair loss
- headache or migraine
- injection site reactions (e.g., skin irritation, swelling, pain, bruising, itching, bleeding)
- muscle or joint pain
- skin irritation, swelling, or pain at the injection site
Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
- abdominal pain
- blurred vision
- rapid, pounding heartbeat
- signs of blood problems (flu-like symptoms, bruises, or unusual tiredness)
- signs of depression (feeling sad, losing interest in things you used to enjoy, weight changes, changes in sleep habits, feelings of guilt or worthlessness, thoughts of suicide)
- signs of heart problems (swollen ankles, shortness of breath, tightness in the chest, decreased ability to exercise, increased heart rate)
- signs of liver problems (yellow eyes or skin, abdominal pain, dark urine or pale stools, easy bruising)
- signs of thyroid problems (weight changes, feeling constantly hot or cold, changes in sleep patterns)
- signs of unusual infections (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
- signs of urinary tract infections (bloody or cloudy urine, need to urinate more frequently, pain on urination, or strong urge to urinate)
Stop taking the medication and seek immediate medical attention if any of the following occur:
- signs of a serious allergic reaction:
- difficulty breathing
- swelling of the face, tongue, or throat
Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.
Are there any other precautions or warnings for this medication?
Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Allergic reactions: In rare cases, some people may develop a severe allergic reaction to this medication. Signs of an allergic reaction include a severe rash, hives, swollen face or throat, or difficulty breathing. If these occur, contact your doctor immediately. The needle cover on the prefilled syringe contains dry natural rubber. Before you start injections, tell your doctor if you have an allergy to rubber or latex.
Blood counts: This medication can decrease the number of neutrophils (a type of white blood cell that helps fight infection) and platelets (which help your blood to clot). Your doctor will do blood tests to monitor this. If you notice any signs of infection (e.g., fever, chills, or sore throat) or unusual bleeding or bruising, contact your doctor immediately.
Depression: Depression has been reported by some people taking interferon medications. If you have a history of depression, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. People with depression should be closely monitored by their doctor. If you develop symptoms of depression such as poor concentration, changes in weight, changes in sleep, decreased interest in activities, or thoughts of suicide while taking this medication, contact your doctor as soon as possible.
Heart problems: This medication may worsen symptoms of heart disease. If you have heart disease such as angina, congestive heart failure, or arrhythmia, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Contact your doctor as soon as possible if you develop symptoms of heart problems such as shortness of breath, chest pain, rapid heartbeat, or swollen ankles.
Kidney failure: Interferon beta-1a may cause decreased kidney function. If you have kidney disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Liver damage: This medication may cause severe liver damage. Although rare, this side effect can be very serious. If you have a history of poor liver function, alcohol abuse, or active liver disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor will test your liver function regularly while you are taking this medication. Contact your doctor as soon as possible if you notice any of the signs of liver damage including yellow eyes or skin, easy bruising of the skin, nausea and vomiting, itching, or abdominal pain.
Seizures: Some people have had seizures while taking this medication, including people who have never had seizures before. If you have seizure disorder, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you have a seizure while taking this medication, you should call your doctor right away.
Thyroid problems: Some people taking this medication develop changes in the function of their thyroid. Symptoms of these changes include feeling cold or hot all the time, a change in weight (gain or loss) without a change in your diet or amount of exercise you get, or feeling emotional. Contact your doctor if you experience these symptoms.
Pregnancy: This medication should not be used during pregnancy. If you become pregnant while taking this medication, contact your doctor immediately. Women who may become pregnant should use effective contraception while taking this medication.
Breast-feeding: This medication may pass into breast milk. If you are a breast-feeding mother and are taking interferon beta-1a, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.
Children: The safety and effectiveness of using this medication have not been established for children and adolescents under 18 years of age.
What other drugs could interact with this medication?
There may be an interaction between interferon beta-1a and any of the following:
- other medications that affect the immune system (e.g., corticosteroids, chemotherapy)
If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:
- stop taking one of the medications,
- change one of the medications to another,
- change how you are taking one or both of the medications, or
- leave everything as is.
An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.
Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.
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