Avonex (interferon beta-1a) is a medicine used to treat relapsing forms of multiple sclerosis (MS), including clinically isolated syndrome (CIS) and relapsing-remitting MS (RRMS). It belongs to a class of medicines called disease-modifying therapies (DMTs).

Multiple Sclerosis (MS):

MS is a condition where the immune system mistakenly attacks the protective covering of nerve fibres (myelin) in the brain and spinal cord. This disrupts signals between the brain and the rest of the body. Relapsing MS involves periods of new or worsening symptoms (relapses), followed by periods of recovery.

How it works:

Interferon beta-1a is a protein naturally produced by the body. As a medicine, it helps to regulate the immune system, reducing the inflammation that causes MS relapses and slowing the accumulation of lesions in the brain and spinal cord.

Avonex does not cure MS, but it can reduce the frequency and severity of relapses and help slow the build-up of disability over time.

Avonex is given as a 30mcg intramuscular injection once a week. Your doctor will confirm the schedule that is right for you.

Before you start:

• Tell your doctor about all other medicines, vitamins, and supplements you take
• Let your doctor know if you have a history of depression, liver problems, thyroid conditions, blood disorders, or seizures
• Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding

How it's given:

• Avonex is injected into the muscle (intramuscularly), most often into the thigh
• Your nurse or doctor will train you or a carer to give the injection safely at home
• Choose a consistent day each week for your injection and try to keep to that routine
• Allow the prefilled syringe or autoinjector to come to room temperature for about 30 minutes before injecting

Managing flu-like symptoms:

Many people experience flu-like symptoms (fever, chills, aching muscles) for the first few months of treatment. Taking a paracetamol or ibuprofen before your injection and at regular intervals for 24 hours afterwards can help reduce these. They usually become less noticeable over time.

• Take your injection as soon as you remember, then resume your regular weekly schedule from that day
• If you are already close to your next scheduled injection, skip the missed one and continue as normal
• Do not give yourself two injections in one week to make up for a missed one

If you are unsure what to do, contact your doctor or MS nurse.

If you think you have injected more than prescribed, call 000 or go to your nearest emergency department straight away.

Signs that something might be wrong include:

• Severe flu-like symptoms
• Unusual tiredness or weakness
• Signs of depression or mood changes that are out of the ordinary

Bring your medicine with you so medical staff know exactly what you received.

• Store in the fridge at 2°C to 8°C
• Do not freeze. If it has been frozen, do not use it
• If needed, Avonex can be stored at room temperature (up to 25°C) for up to 7 days. Once removed from the fridge, do not put it back
• Keep in the original packaging to protect from light
• Keep out of reach of children and pets

Dispose of used syringes safely in a sharps container.

Side effects are common, particularly in the early months of treatment, but many people find they settle over time.

• Flu-like symptoms: Fever, chills, muscle aches, and fatigue are very common, especially after the first few injections. These usually improve after the first few months
• Injection site reactions: Pain, redness, or bruising at the injection site. Rotate sites and use correct technique
• Headache: Fairly common, particularly around the time of injection
• Depression and mood changes: Interferon beta medicines can sometimes worsen or trigger depression. Tell your doctor immediately if you notice significant changes in your mood
• Liver changes: Your liver enzymes may rise during treatment. This is monitored with regular blood tests
• Thyroid problems: Some people develop changes in thyroid function during treatment
• Allergic reactions: Rare, but possible. Seek immediate help if you develop difficulty breathing, swelling of the face, or a severe skin reaction

Contact your doctor, MS nurse, or pharmacist if any side effect is troubling you.

Tell your doctor and pharmacist about everything you are taking before starting Avonex. Key things to be aware of:

• Immunosuppressants: Using Avonex alongside other medicines that suppress the immune system requires careful monitoring
• Medicines processed by the liver: Avonex can affect liver enzyme activity, which may alter how some medicines are processed by the body
• Live vaccines: Discuss any upcoming vaccinations with your doctor before receiving a live vaccine during treatment

Never start, stop, or change any medicine without speaking to your doctor first.

How long does it take for Avonex to work?

Avonex does not produce immediate results you will feel from day to day. It works gradually over time to reduce the frequency of relapses and slow disease progression. Most studies assess its effect over 1 to 2 years. You may not notice a clear difference quickly, but regular MRI scans and neurological assessments will help your doctor track how you are responding.

Does Avonex stop MS from progressing?

Avonex can slow the accumulation of disability and reduce the number of relapses, but it does not stop MS progression entirely. It is one of several disease-modifying therapies available, and your neurologist will help you choose the right option for your situation.

What if I find the injections difficult?

Many people feel anxious about self-injecting at first. Your MS nurse can provide training and ongoing support. The Avonex autoinjector (Avonex PEN) is designed to make injection easier, particularly if you find using a syringe difficult. Ask your nurse or pharmacist about this option.

Ace provides accurate and independent information medically reviewed on prescription medications. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment.