Interferon Beta-1a
Avonex is a brand-name medication containing interferon beta-1a, used to treat relapsing forms of multiple sclerosis (MS). It is administered as a weekly injection and helps reduce the frequency of MS relapses and slow the progression of disability.
Avonex is an injectable interferon therapy used to manage relapsing multiple sclerosis by reducing relapse frequency and delaying disability progression.
Key facts at a glance
- RxNorm
- 153326
- Generic
- Avonex
- Class
- brand-name
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- —
- Forms
- —
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Avonex is prescribed for relapsing forms of multiple sclerosis (RMS), including clinically isolated syndrome (CIS), relapsing-remitting MS (RRMS), and secondary progressive MS with relapses. It is not indicated for primary progressive MS.
As an interferon beta-1a, Avonex is an immunomodulator that reduces inflammation and modifies immune system activity. It is believed to decrease immune cells crossing the blood-brain barrier and reduce inflammatory attacks on the central nervous system, though its exact mechanism in MS is not fully understood.
Avonex is administered via intramuscular injection once weekly. Common side effects include flu-like symptoms (fever, chills, muscle aches), injection site reactions, and fatigue. It should be used with caution in patients with depression, seizure disorders, or liver problems. Regular monitoring by a healthcare provider is required.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed September 2, 2026. · Read our editorial policy