Interferon Beta-1a: uses, dosing, side effects & brands
Interferon Beta-1a is an interferon beta sold in the U.S. under 2 brand and generic names, for multiple sclerosis. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Drug class
- Interferon Beta
- Treats (across its forms)
- Multiple Sclerosis
- Available as
- Kit · Injectable
- Sold as
- 2 products — Avonex and Rebif
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
How Avonex is dosed
From the FDA label for Avonex (application BLA103628). Other interferon beta-1a products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
For intramuscular use only ( 2.1 ) Recommended dose: 30 micrograms once a week ( 2.1 ) AVONEX may be titrated, starting with 7.5 micrograms for first week, to reduce flu-like symptoms ( 2.1 ) Increase dose by 7.5 micrograms each week for next 3 weeks until recommended dose of 30 micrograms ( 2.1 ) See patient instructions for use for complete administration instructions ( 2.2 ) Perform first injection under the supervision of an appropriately qualified health care professional ( 2.2 ) Analgesics and/or antipyretics on treatment days may help ameliorate flu-like symptoms ( 2.3 ) 2.1 Dosing Information AVONEX is administered intramuscularly. The recommended dose is 30 micrograms once a week. To reduce the incidence and severity of flu-like symptoms that may occur when initiating AVONEX therapy at a dose of 30 micrograms, AVONEX may be started at a dose of 7.5 micrograms and the dose may be increased by 7.5 micrograms each week for the next three weeks until the recommended dose of 30 micrograms is achieved (see Table 1 ). An AVOSTARTGRIP™ kit containing 3 titration devices can be used for titration and is to be used only with AVONEX Prefilled Syringes. Table 1: Schedule for Dose Titration 1 Dosed once a week, intramuscularly AVONEX Dose 1 Recommended Dose Week 1 7.5 micrograms 1/4 dose Week 2 15 micrograms 1/2 dose Week 3 22.5 micrograms 3/4 dose Week 4+ 30 micrograms full dose…
Everything below is the FDA label for Avonex (kit). Interferon Beta-1a is also sold as injectable, and those are different medicines to take — follow the label for the one you were prescribed.
Avonex side effects
The following serious adverse reactions are discussed in more detail in other sections of labeling: Depression, Suicide, and Psychotic Disorders [see Warnings and Precautions ( 5.1 )] Hepatic Injury [see Warnings and Precautions ( 5.2 )] Anaphylaxis and Other Allergic-Reactions [see Warnings and Precautions ( 5.3 )] Injection Site Reactions Including Necrosis [see Warnings and Precautions ( 5.4 )] Congestive Heart Failure [see Warnings and Precautions ( 5.5 )] Decreased Peripheral Blood Counts [see Warnings and Precautions ( 5.6 )] Thrombotic Microangiopathy [see Warnings and Precautions ( 5.7 )] Pulmonary Arterial Hypertension [see Warnings and Precautions ( 5.8 )] Seizures [see Warnings and Precautions ( 5.9 )] Autoimmune Disorders [see Warnings and Precautions ( 5.10 )] Laboratory Tests [see Warnings and Precautions ( 5.11 )] The most common adverse reactions (at least 5% more frequent on AVONEX than on placebo) were flu-like symptoms including chills, fever, myalgia, and asthenia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Biogen at 1-800-456-2255 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of AVONEX cannot be directly compared to rates in clinical trials of other drugs and may not reflect the rates…
Who shouldn’t take Avonex
AVONEX is contraindicated in patients with a history of hypersensitivity to natural or recombinant interferon beta, or any other component of the formulation [see Warnings and Precautions ( 5.3 )] . The formerly available lyophilized vial formulation of AVONEX is contraindicated in patients with a history of hypersensitivity to albumin (human). History of hypersensitivity to natural or recombinant interferon beta, albumin or any other component of the formulation ( 4 )
Every interferon beta-1a product we track (2)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
| # | Drug | Rating | Type | Form | Generic? | Pharmacy pays | |
|---|---|---|---|---|---|---|---|
| 1 | Not yet rated | Prescription | Kit | No data | — | View → | |
| 2 | Not yet rated | Prescription | Injectable | No data | — | View → |
What people report to the FDA about interferon beta-1a
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 1,280 reports naming interferon beta-1a, and the FDA flagged 86% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- multiple sclerosis relapse97 reports
- multiple sclerosis56 reports
- fall50 reports
- maternal exposure during pregnancy47 reports
- headache45 reports
- fatigue41 reports
- gait disturbance38 reports
- dizziness35 reports
Read these as a signal, not a rate. A report does not mean interferon beta-1a caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved August 25, 2026.
Related calculators
Frequently asked questions
What is Avonex?
Avonex (Interferon Beta-1a) is an interferon beta used to treat Multiple Sclerosis.
What kind of drug is interferon beta-1a?
The FDA classifies interferon beta-1a as an interferon beta. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take interferon beta-1a with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run interferon beta-1a against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is interferon beta-1a sold under?
We track 2 interferon beta-1a-containing products in the U.S.: Avonex and Rebif. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does interferon beta-1a come in?
Across the brands we track, interferon beta-1a is currently marketed as kit and injectable, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic interferon beta-1a?
We do not currently list a generic-labelled interferon beta-1a product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Interferon Beta-1a: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/interferon-beta-1a
- MLA
- “Interferon Beta-1a: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/interferon-beta-1a.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for interferon beta-1a on DailyMed (NIH) ↗.