Interferon Beta for Multiple Sclerosis

Browse By All Topics


Interferon Beta for Multiple Sclerosis


Generic NameBrand Name
interferon betaAvonex, Betaseron, Extavia, Rebif

Avonex is injected into the muscle of the thigh, upper arm, or buttock once a week. Rebif is injected beneath the skin 3 times a week. Betaseron and Extavia are injected beneath the skin every other day.

How It Works

The interferon beta medicines resemble the natural interferon the body produces during a response by the immune system to disease. It is not completely clear how interferon beta medicines work in people who have multiple sclerosis (MS). But it is known that they affect the immune system and also help fight viral infections. They also work by preventing inflammation and demyelination in the central nervous system.

Why It Is Used

Interferon beta is used to treat people with MS who have relapses followed by periods of recovery (relapsing-remitting MS). Findings from clinical trials show that people treated soon after being diagnosed with MS may have better results than those who delay treatment.

The National Multiple Sclerosis Society recommends that people with a definite diagnosis of MS and active, relapsing disease start treatment with interferon beta or glatiramer. This group adds that treatment with medicine may also be considered after the first attack in some people who are at a high risk for MS.1

Some people have only one episode of a neurological symptom such as optic neuritis. Yet MRI tests suggest these people have MS. This is known as a clinically isolated syndrome. Many of these people go on to develop MS over time. In some cases, doctors will prescribe medicine (either interferon beta or glatiramer) for people who have had a clinically isolated syndrome. These medicines, when taken early or even before you have been diagnosed with MS, may keep the disease from getting worse or extend your time without disease.2

Interferon beta (Betaseron) has been shown to benefit people who have secondary progressive MS that is relapsing.

The interferon beta medicines have been tested only in people age 18 and older. But they are frequently used in children who have MS.

How Well It Works

Studies have shown that:

  • Interferon beta decreases the number of relapses in relapsing multiple sclerosis.3
  • People who take interferon beta have less disability and fewer areas of damage (lesions) on the brain as seen on MRI.3
  • Treatment with interferon beta may reduce the number of attacks and slow disease progression in people who have clinically isolated syndrome and relapsing-remitting MS.4
  • Treatment with interferon beta may also reduce the number of attacks and slow disease progression in people who have secondary progressive MS.5

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

  • Usually the benefits of the medicine are more important than any minor side effects.
  • Side effects may go away after you take the medicine for a while.
  • If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.

Call 911 or other emergency services right away if you have:

  • Trouble breathing.
  • Swelling of your face, lips, tongue, or throat.

Call your doctor right away if you have:

Check with your doctor if you have:

  • Flu-like symptoms for 1 to 2 days after an injection. Symptoms may include:
    • Chills.
    • Fever.
    • Headache.
    • Muscle or joint pain.
    • Nausea.
    • Sweating.
  • Itching, swelling, or other skin changes at the injection site.
  • Slow or fast heartbeat.
  • Stomach pain.

Common side effects of this medicine include:

  • Constipation or diarrhea.
  • Dizziness.
  • Heartburn or indigestion.
  • Hoarseness or loss of voice.
  • Unusual tiredness or weakness.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

The flu-like symptoms—such as fatigue, chills, fever, and muscle aches—that people have for 1 to 2 days after an injection may be temporarily debilitating for some people. But these symptoms usually go away after 2 to 3 months of treatment. Taking a pain reliever such as ibuprofen or acetaminophen just before and after each injection may help reduce these symptoms. Taking interferon beta at bedtime may also help.

Follow your doctor's instructions on how to use this medicine. Do not give yourself an injection in the same place twice in a row. Always change the site of the next injection.

Some people treated with interferon have become depressed (feeling sad, feeling low, or feeling bad about oneself). 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.

The National Multiple Sclerosis Society recommends that people who have a definite diagnosis of MS and active, relapsing disease start treatment with interferon or glatiramer. The group adds that medicine may also be considered after the first attack in some people at high risk for MS but before it is diagnosed.1

In addition to side effects, there are some drawbacks to treatment with interferon beta:

  • Treatment does not work for some people. And it is hard to predict whether the medicine will help a particular person.
  • Some experts worry that in some people interferon may become less effective after long-term use because the body may produce neutralizing antibodies that may reduce the effect of the medicine.
  • Treatment is costly.

Talk with your doctor if your MS relapses have not become less severe or less frequent after 6 months of interferon therapy. It may be time to consider other medicines.

Taking medicine

Medicine is one of the many tools your doctor has to treat a health problem. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.

There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.

Advice for women

Do not use this medicine if you are pregnant or planning to get pregnant. If you need to use this medicine, talk to your doctor about how you can prevent pregnancy.


Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.



  1. National Clinical Advisory Board of the National Multiple Sclerosis Society (2008). Disease Management Consensus Statement. New York: National Multiple Sclerosis Society. Available online:
  2. Faggiano CM, et al. (2008). Recombinant interferon beta or glatiramer acetate for delaying conversion of the first demyelinating event to multiple sclerosis. Cochrane Database of Systematic Reviews (2).
  3. Rowland LP (2010). Multiple sclerosis. In LP Rowland, TA Pedley, eds., Merritt’s Neurology, 12th ed., pp. 902–918. Philadelphia: Lippincott Williams and Wilkins.
  4. Nicholas R, Chataway J (2009). Multiple sclerosis, search date June 2008. Online version of BMJ Clinical Evidence:
  5. Goodin DS, et al. (2002, reaffirmed 2008). Disease modifying therapies in multiple sclerosis: Report of the therapeutics and technology assessment subcommittee of the American Academy of Neurology and the MS Council for Clinical Practice Guidelines. Neurology, 58(2): 169–178.


ByHealthwise Staff
Primary Medical ReviewerAdam Husney, MD - Family Medicine
Primary Medical ReviewerAnne C. Poinier, MD - Internal Medicine
Specialist Medical ReviewerBarrie J. Hurwitz, MD - Neurology
Last RevisedMay 14, 2012

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use.

How this information was developed to help you make better health decisions.

© 1995-2012 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.