AVONEX safety and side effects

Depression, suicidal thoughts, hallucinations, or other behavioral health problems

Some people taking AVONEX may develop mood or behavior problems, including irritability (getting upset easily), depression (feeling hopeless or feeling bad about yourself), nervousness, anxiety, aggressive behavior, thoughts of hurting yourself or suicide, or hearing or seeing things that others do not hear or see (hallucinations).

Liver problems, or worsening of liver problems including liver failure and death. Tell your healthcare provider right away if you have any of these symptoms:

• nausea
• loss of appetite
• tiredness
• dark colored urine and pale stools
• yellowing of your skin or the white part of your eye
• bleeding more easily than normal
• confusion
• sleepiness

During your treatment with AVONEX you will need to see your healthcare provider regularly and have regular blood tests to check for side effects. Tell your healthcare provider about all the medicines you take and if you drink alcohol before you start taking AVONEX.

Serious allergic reactions and skin reactions. Symptoms of serious allergic and skin reactions may include:

• itching
• swelling of the face, eyes, lips, tongue, or throat
• trouble breathing
• anxiousness
• feeling faint
• skin rash, hives, sores in your mouth, or your skin blisters and peels

Get emergency help right away if you have any of these symptoms. Talk to your healthcare provider before taking another dose of AVONEX.

Injection site reactions

AVONEX may cause redness, pain, itching, or swelling at the place where your injection was given. Call your healthcare provider right away if an injection site becomes swollen and painful or the area looks infected. You may have a skin infection or an area of severe skin damage (necrosis) requiring treatment by a healthcare provider.

Heart problems, including heart failure

Some people 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 heartbeat, chest pain, and heart attack or a heart muscle problem (cardiomyopathy)

Blood problems

AVONEX can affect your bone marrow and cause low red and white blood cell, and platelet counts. In some people, these blood cell counts may fall to dangerously low levels.

Thrombotic microangiopathy (TMA)

TMA is a condition that involves injury to the smallest blood vessels in your body. TMA can also cause injury to your red blood cells (the cells that carry oxygen to your organs and tissues) and your platelets (cells that help your blood clot) and can sometimes lead to death.

Pulmonary arterial hypertension

Pulmonary arterial hypertension can occur with interferon beta products, including AVONEX. Symptoms may include new or increasing fatigue or shortness of breath. Contact your healthcare provider right away if you develop these symptoms.

Seizures

Some people have had seizures while taking AVONEX, including people who have never had seizures before. Tell your healthcare provider right away if you have a seizure.

Autoimmune diseases

Problems with easy bleeding or bruising (idiopathic thrombocytopenia), thyroid gland problems (hyperthyroidism and hypothyroidism), and autoimmune hepatitis have happened in some people who use AVONEX.