A to Z of MS
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A to Z of MS Interferon beta 1a (Avonex)
Avonex is a disease modifying drug licensed for relapsing remitting MS and some people with secondary progressive MS. Studies have shown that on average Avonex reduces the relapse rate in people with relapsing remitting MS by about a third and also reduces the severity of those relapses that do occur.
Avonex is also licensed for clinically isolated syndrome, an individual's first neurologic episode. The 2009 ABN prescribing guidelines state that neurologists may consider the use of beta interferon for people within 12 months of a clinically isolated syndrome when MRI evidence predicts a high likelihood of recurrent episodes.
Avonex is prescribed under the Department of Health's Risk-sharing Scheme.
How beta interferon works
Interferons are proteins that occur naturally in the immune system. It is thought that beta interferon acts by reducing both inflammation and the immune response that is attacking the body's own myelin.
How is Avonex given?
Avonex is injected into a muscle once a week. A version that requires fewer injections is being developed.
Side effects and contraindications
Flu like symptoms following injections. These tend to reduce over time and are usually no longer a problem after three months on treatment.
Jacobs LD, et al.
Intramuscular interferon beta-1a for disease progression in relapsing multiple sclerosis.
Annals of Neurology 1996;39(3):285-294.
Association of British Neurologists (ABN)
Revised (2009) guidelines for prescribing in multiple sclerosis.
London; ABN: November 2009.
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Patient Information Leaflet
- Avonex (medicines.org.uk website)
- Webcast on drug therapy
- Neurologist Prof David Bates addresses some of the questions people ask about disease modifying drugs
- Watch the webcast