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Rebif: Usage for MS and Side Effects of Interferon Beta-1a

Pharmacist-checked answers on the uses and side effects of Rebif

Interferon beta-1a is an injectable drug used to treat various forms of multiple sclerosis (MS), including clinically isolated syndrome, relapsing-remitting MS and active secondary progressive disease. Interferon beta-1a is sold under the brand names Rebif and others. In this article, we answer some of the most frequently asked questions about Rebif.

The content on this page is provided for informational purposes only. If you have any questions or concerns about your treatment, you should talk to your doctor, pharmacist, or healthcare professional. This is particularly important if you are taking multiple medications or have any existing medical conditions.

What is Rebif?

Rebif, with the active ingredient interferon beta-1a, is an injectable medicine from the interferon family and is used to treat various forms of multiple sclerosis. Natural interferons are cytokines, which are proteins released by the immune system to regulate your immune response to germs, viruses, bacteria and cancer.

Interferon beta-1a is classified as a disease-modifying therapy for MS. This means that although it is not a cure, it can reduce the number of relapses a person has and slow the progression of the disease. Interferon beta-1a's mode of action is not yet fully understood, but it is thought to reduce both inflammation and the immune response that attacks myelin.

There are three forms of interferons: Alpha (α), Beta (β) and Gamma (γ), which are grouped as type I (alpha and beta forms) and type II (gamma). While interferon beta-1a is used to treat MS, others are used for diseases such as cancer, hepatitis C and rheumatoid arthritis.

What is Rebif used for?

Rebif or interferon beta-1a is used to treat relapsing forms of multiple sclerosis. These include:

The clinically isolated syndrome.

Clinically isolated syndrome refers to a single episode of neurological symptoms that lasts at least 24 hours. Because clinically isolated syndrome is a single episode of symptoms, it is sometimes considered a different disease from MS; others consider it the earliest form of relapsing-remitting MS.

Regardless, the purpose of interferon beta 1a therapy is to prevent or slow the progression of relapsing-remitting MS. A study published in 2015 found that people who received 44 mcg of Rebif injections three times a week were about 50% less likely to have progression of relapsing-remitting MS than people who received a placebo.

The relapsing-remitting disease

While a single episode of neurological symptoms is called a clinically isolated syndrome, the second episode of symptoms means that the disease has progressed to relapsing-remitting MS or relapsing-remitting disease.

Nevertheless, the purpose of interferon beta 1a therapy in people with relapsing-remitting MS is to slow the progression of the disease and reduce the number of relapses.

The active secondary progressive disease

Secondary progressive MS (SPMS) or secondary progressive disease is characterized by a steady worsening of symptoms rather than marked relapses (although relapses may occur). SPMS is considered "active" when relapses occur.

As with clinically isolated syndrome and relapsing-remitting MS, treatment with Rebif is intended to slow the progression of the disease.

What are the effects of Rebif?

Although all the effects of Rebif are not yet fully established, some effects on the immune system are known. The body's interferons are proteins that play a role in regulating your immune system.

Multiple sclerosis is an autoimmune disease, which means that the immune system mistakenly attacks healthy cells in the body. In MS, the immune system attacks the myelin sheath, a protective layer made of a fatty substance (myelin) that protects the fibers (axons) of the central nervous system (CNS). This leads to scars (or plaques) that cause the symptoms associated with MS.

Interferon beta-1a helps slow the rate at which the immune system damages the myelin sheath, which can help prevent relapses and slow the progression of the disease. Interferon beta-1a or Rebif is not a cure for MS (there is no cure yet) but it is considered a disease-modifying therapy.

How effective is Rebif?

According to the MS Society, beta interferon therapies, including Rebif, are rated "moderate" in terms of effectiveness. In studies, the average number of relapses decreased by 33% compared to people taking placebos.

This study looked at the effectiveness of treatment with Rebif:

Was a two year study with a population of 560 participants taking either Rebif 22 mcg (189 people), Rebif 44 mcg (184 people) and placebo (187 people). At the end of the study, 533 participants remained. The study found that people taking Rebif experienced fewer relapses and slower progression of disease compared to the placebo group.

What are the side effects of Rebif?

Flu-like symptoms

Flu-like symptoms are common side effects of interferon beta-1a, including

  • fever
  • chills
  • fatigue
  • sweating
  • muscle aches
  • Nausea

These flu-like symptoms are not caused by an actual flu virus but are due to your body getting used to the new treatment drug. They often decrease as your body adjusts to the treatment. To reduce the number of symptoms, treatment is started at a lower dose and increased over a period of four or five weeks before reaching the full dose.

You should talk to your doctor about any flu-like symptoms you experience.

Symptoms at the injection site

You may experience symptoms at the site where an injection is given:

  • Redness
  • pain
  • Swelling
  • Color change (blue or black)
  • Discharge of fluid

If you experience any of these symptoms, you should talk to your healthcare provider, as they can lead to infection. Your doctor will advise or share tips on how to avoid or reduce these symptoms.

Mental health and behavioral problems

It has been found that interferon beta-1a increases the risk of mood or behavioral problems including:

  • Hallucinations
  • Irritability
  • Nervousness
  • Anxiety
  • Aggressive behavior

Similarly, suicide attempt is included in this list: The risk of these symptoms is thought to be higher in people with a history of depression. Therefore, do not take Rebif if you have depression. You should speak to your doctor immediately if you experience any of these symptoms.

Liver problems

Rebif has been associated with liver problems, which may include the following symptoms:

  • Yellowing of the skin and/or the whites of your eyes.
  • Dark colored urine and light-colored stools
  • Nausea
  • Tiredness
  • Loss of appetite
  • Bleeding more easily than usual
  • Confusion
  • Drowsiness

Talk to your doctor straight away if you experience any of these symptoms.

Severe allergic and skin reactions

Signs of a severe allergic reaction should be considered a medical emergency. Seek urgent medical attention if you experience any of the following signs of an allergic reaction:

  • Swelling of the face, lips, tongue or throat.
  • A skin rash that may include itchy, red, swollen, blistering or peeling skin
  • Tightness in the chest or throat
  • Wheezing or difficulty breathing

This is not a comprehensive list of side effects that may occur when taking interferon beta-1a. The risk of some side effects may be related to your medical history, so it is important to discuss any medical conditions you have or have had, including mental illness and liver problems, as well as any medicines or supplements you are taking.

Also read the leaflet that comes with Rebif for more details about the side effects that may occur.

What is the difference between Avonex and Rebif?

As with Rebif, interferon beta-1a is the active ingredient in Avonex. However, there are some major differences, including

The injection method

Avonex is injected intramuscularly, i.e. into the muscle, while Rebif is injected subcutaneously, i.e. under the skin.

Dosage schedule

Avonex injections are given once a week. It can also be titrated starting with 7.5 micrograms for first week, to reduce flu-like symptoms. Dose is increased by 7.5 micrograms each week for next 3 weeks until recommended dose of 30 micrograms while Rebif injections are required three times a week. There must be at least 48 hours between injections. It is recommended that Rebif injections are given at the same time and on the same days each week (e.g. Monday, Wednesday and Friday evenings).


Avonex contains 30 mcg of the active ingredient, interferon beta-1a, in a 0.5 mL solution. Rebif is available in a strength of 8.8 mcg in a 0.2 mL solution, 22 mcg in a 0.5 mL solution and 44 mcg in a 0.5 mL solution. The 8.8 mcg strength of Rebif is used during the titration period (at the start of treatment when the dosage is increased over several weeks before reaching full dosage), while the 22 mcg and 44 mcg strengths can both be prescribed as full dosage strengths.

The decision whether Avonex or Rebif is the right treatment for you should be made in consultation with your doctor and is based on aspects such as personal preferences and lifestyle, the severity of your symptoms and your health history.

What do I have to bear in mind whilst taking Rebif

During interferon treatment, blood clots can occur in the small blood vessels and have effects on the kidneys for several weeks to several years after the start of treatment. The treating doctor must monitor blood pressure, blood (platelet count) and kidney function during interferon therapy.

In about 25% of people treated with interferon, antibodies form that can weaken the effect of the interferon. The treating doctor should reconsider interferon therapy if it has little effect and neutralizing antibodies are detected in the blood.

Can I inject Rebif at home?

It is possible to inject interferon beta-1a from home. There are three different syringe options Rebif prefilled syringe, Rebiject II auto injector and Rebif Rebidose auto injector. You should only use Rebif prefilled syringe and Rebiject II auto injector after proper training from a medical professional.

Interferon injectables are usually stored in the refrigerator at 2 to 8°C.

Recommended preventive measures against injection site reactions include:

  • Remove the pre-filled syringe from the refrigerator approximately 30 minutes before administration and allow it to warm to room temperature.
  • Wash hands thoroughly before injecting.
  • Thoroughly clean the skin at the injection site. Soap and water are less irritating to the skin than alcohol swabs. If alcohol swabs are used (e.g., when travelling or in hospital), allow the skin to dry for at least 60 seconds after use.
  • Change the injection site regularly
  • Cool swellings at the injection site with a cold compress. Treat swellings that last longer than 1 day with heat
  • Treat the rash with ointments containing anti-allergic substances (antihistamines) such as diphenhydramine (Dermodrin or Benadryl ointment), hydrocortisone cream or substances from the witch hazel plant.

The content on this page is provided for informational purposes only. If you have any questions or concerns about your treatment, you should talk to your doctor, pharmacist, or healthcare professional. This is particularly important if you are taking multiple medications or have any existing medical conditions.