Avonex Administration Pack IM

In Depth

Generic Name: INTERFERON BETA-1A PREFILLED SYRINGE - INJECTION
Pronounced: (in-ter-FEER-on BAY-tuh)

Avonex Administration Pack IM Side Effects

Pain, swelling, or redness at the injection site may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.

Flu-like symptoms such as headache, fatigue, fever, chills, and muscle aches may occur when you first start this medication. These symptoms usually last about a day after the shot and improve or go away after a few months of continued use. You can minimize these side effects by injecting this medicine at bedtime and using fever reducers/pain relievers such as acetaminophen or ibuprofen before each dose. Consult your doctor or pharmacist for more information.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

mental/mood changes (e.g., depression, thoughts of suicide, new or worsening psychiatric symptoms)
hair loss
vision changes
persistent fatigue
numbness/tingling/swelling of the hands/ankles/feet
muscle weakness
trouble breathing
sudden weight gain
gradual change in weight (without a change in diet or exercise)
cold or heat intolerance
slow/fast/irregular heartbeat
easy bleeding or bruising
signs of infection (e.g., fever, persistent sore throat)
yellowing eyes or skin
persistent nausea/vomiting
stomach/abdominal pain
dark urine

Get medical help right away if any of these rare but very serious side effects occur:

chest pain
seizures

A very serious allergic reaction to this drug is unlikely, but get medical help right away if it occurs. Symptoms of a serious allergic reaction may include: