Email This Page to a Friend or Loved One

Enter your email address and your friend or loved one's email address and submit.

  • Submit   
       or    Cancel

AVONEX (interferon beta-1a) respects and protects your privacy.
Read our Privacy Policy



Experienced in the fight against relapsing MS

When you and your doctor choose a treatment for relapsing multiple sclerosis (MS), you need to weigh the potential benefits of a therapy against the potential risks and side effects. That's why it may be helpful to know that once-a-week AVONEX has a well-understood safety profile.

Before a treatment can be approved by the FDA, its safety and effectiveness have to be carefully studied in clinical trials. The safety of AVONEX was studied in 2 well-controlled clinical trials, the same trials that proved AVONEX reduces flare-ups and delays physical disability progression.

As a result of these trials, AVONEX is approved by the FDA to treat relapsing forms of MS to decrease the number of flare-ups and slow the occurrence of some of the physical disability that is common in people with MS. AVONEX is also approved for use in people who have experienced a first attack and have lesions consistent with MS on their MRI. Before beginning treatment, you should discuss with your healthcare provider the potential benefits and risks associated with AVONEX.

AVONEX has an established heritage of treating relapsing MS. In fact, once-a-week AVONEX was FDA approved more than 17 years ago. However, because the longest clinical trial of AVONEX lasted for 3 years, the safety and effectiveness of treatment with AVONEX beyond 3 years is not known.

A well-understood safety profile

Here is some Important Safety Information you should know before starting once-a-week AVONEX.

Some people may have certain medical conditions that need to be considered before they start AVONEX. Before taking AVONEX, you should tell your healthcare provider if you:

  • are being treated for a mental illness, or had treatment in the past for any mental illness, including depression and suicidal behavior
  • have or had bleeding problems or blood clots, have or had low blood cell counts, have or had liver problems, have or had seizures (epilepsy), have or had heart problems, have or had thyroid problems
  • have or had any kind of autoimmune disease (where the body's immune system attacks the body's own cells), such as psoriasis, systemic lupus erythematosus, or rheumatoid arthritis
  • drink alcohol
  • are pregnant or plan to become pregnant. It is not known if AVONEX will harm your unborn baby. Tell your healthcare provider if you become pregnant during your treatment with AVONEX
  • are breastfeeding or plan to breastfeed. It is not known if AVONEX passes into your breast milk. You and your healthcare provider should decide if you will use AVONEX or breastfeed. You should not do both

AVONEX can cause serious side effects, such as heart problems, including heart failure. While AVONEX is not known to have any 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 taking AVONEX. If you already have heart failure, AVONEX may cause your heart failure to get worse. Call your healthcare provider right away if you have worsening symptoms of heart failure such as shortness of breath or swelling of your lower legs or feet while using AVONEX.

Some people using AVONEX may have other heart problems including:

  • low blood pressure
  • fast or abnormal heart beat
  • chest pain
  • heart attack or a heart muscle problem (cardiomyopathy)

In addition, if you are allergic to AVONEX or any of the ingredients in AVONEX, do not take AVONEX. And if you experience an allergic reaction to AVONEX, stop taking AVONEX and talk to your doctor about your treatment options.

After you review the benefits and risks of AVONEX with your doctor, he or she may ask you to have regular blood tests to make sure your liver is functioning properly.

Most people who take AVONEX have flu-like symptoms early during the course of therapy. Usually, these symptoms last for a day after the injection. You may be able to manage these flu-like symptoms by taking over-the-counter pain and fever reducers. For many people, these symptoms lessen or go away over time. Symptoms may include muscle aches, fever, tiredness, and chills.

We're here to help

If you still have concerns, remember – you're not alone. You should always call your doctor's office with any questions. You can also speak with an ActiveNurse. These MS-trained nurses are available by phone 24/7 and are dedicated to making you feel more comfortable and confident with taking once-a-week AVONEX. Call an ActiveNurse today at 1-800-456-2255 for answers to your questions about AVONEX or its side effects.

You can report side effects to the FDA online or by calling 1-800-FDA-1088.


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

Please see the full Prescribing Information and Medication Guide for additional important safety information. This information is not intended to replace discussions with your healthcare provider.


Kelly: Why I choose AVONEX


Additional Stories

See all stories