Common Side Effects

Because no two people are exactly alike, it’s impossible to know what side effects, if any, you may have while taking a multiple sclerosis (MS) medication. While all MS drugs are not the same, on average, the most common side effects of injectable MS therapies are injection-site reactions (ISRs) and flu-like symptoms (FLS).

Injection site reactions (ISRs)

ISRs occur in the skin near where the needle entered your skin. ISRs can include swelling, pain, itching, and lumps. These types of reactions are common with injections made subcutaneously and, as the images below help illustrate, they may cause skin discomfort. Avonex may cause ISRs, but in comparative studies AVONEX had the lowest rate of ISRs of any injectable MS treatment.

More severe ISRs include:

• Lipoatrophy, or loss of fat cells, resulting in a dent in your skin
• Necrosis, or death of tissue around the site of the injection

If you're concerned about ISRs, be sure to discuss them with your doctor as you explore your MS treatment options.

Flu-like symptoms (FLS)

When most people begin taking AVONEX, they experience the fever, chills and aches associated with the flu. Many people find these symptoms usually get milder or go away over time, as their bodies have time to adjust to the medication. To help you cope with these symptoms, talk to your healthcare provider, who may suggest you stay hydrated, take over-the-counter medicines for the pain and fever, and take AVONEX at the time of day that works best for you.

Find out how Jane and Heather have learned to deal with flu-like symptoms.
View video

Don't let the possibility of side effects keep you from staying on treatment

A five-year study conducted by interviewing people with MS and reviewing their medical charts compared their rates of injection site reactions (ISRs) and flu-like symptoms (FLS).

Severe reactions were seen in 10% of people taking Copaxone. High fever with general weakness was seen in 7% of people taking Rebif or Betaseron and 24% of people taking AVONEX. In this five-year study, people taking Copaxone were the least likely to take their medication as prescribed. People taking AVONEX were the most likely. This study included other factors that could affect a person's ability to take his or her medication as prescribed.

For more about the possible side effects of AVONEX, see Important Safety Information and be sure to talk to your doctor.

Safety and efficacy of treatment with AVONEX beyond three years is not known.

Talk with your doctor to find out if AVONEX is right for you.