MS Treatment Side Effects

AVONEX can cause serious side effects, so before you start therapy, you should talk with your healthcare provider about the possible benefits of AVONEX and its possible side effects to decide if AVONEX is right for you.

Sometimes interferons, including AVONEX, make people feel sad. If you are taking AVONEX, and feel unusually sad, you should tell a family member or friend right away and call your healthcare provider as soon as possible.

Some people have had severe allergic reactions, a drop in their red or white blood cell levels, a drop in cells that help to form blood clots, heart problems, changes in their thyroid function, or seizures.

Your liver may be affected by taking AVONEX and a few patients have developed severe liver injury. Your healthcare provider may ask you to have regular blood tests to make sure that your liver is working properly. If your skin or the whites of your eyes become yellow, or if you are bruising easily, you should call your healthcare provider immediately.

AVONEX has not been studied in pregnant women. If you become pregnant while taking AVONEX, you should stop taking AVONEX immediately, tell your healthcare provider, and consider enrolling in the AVONEX Pregnancy Registry by calling 1.800.456.2255.

Most people who take AVONEX have flu-like symptoms (fever, chills, sweating, muscle aches, and tiredness) early during the course of therapy. For many people, these symptoms lessen or go away over time. Talk to your healthcare provider if these symptoms continue longer than the first few months of therapy, or if they are difficult to manage. In addition, you can refer to the Patient Medication Guide. This information is not intended to replace discussions with your healthcare provider.

Since AVONEX was approved in 1996, healthcare providers have developed successful ways to manage some of the more common AVONEX side effects, such as flu-like symptoms.

You should discuss ways to manage any AVONEX side effects you may have with your healthcare provider.

Few people quit due to AVONEX side effects

Very few people stop taking AVONEX because of side effects such as flu-like symptoms (fever, chills, sweating, muscle aches, and tiredness).

In a 2-year study, very few people (4%) stopped taking AVONEX due to side effects.

In a longer, 8-year follow-up study, even fewer people (2%) stopped taking AVONEX due to side effects.

Injection site reactions

AVONEX is the only MS therapy delivered by an injection into the muscle (IM). All other injectable MS therapies are delivered under the skin (subcutaneous). In clinical studies, only 3 out of 100 people taking AVONEX had reported injection-site reactions often seen with other MS therapies.

Read tips to help make AVONEX injections more manageable.

For more information, refer to the patient Medication Guide. This information is not intended to replace discussions with your healthcare provider.

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