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Generic name: interferon beta-1a [in-ter-FEAR-on-BAY-ta]
Drug class: interferons

What is Avonex?

Avonex contains human proteins. The body uses interferons to fight viruses.Avonex treats relapsing multiple sclerosis in adults, including clinically isolated syndromes, relapsing remitting diseases, and secondary active progressive disease.Avonex does not cure MS. It will reduce the number of symptoms that recur.


Avonex may harm your liver. If you experience symptoms like nausea, fatigue, confusion, easy bleeding or bruising, dark urine or clay-coloured stool, yellowing skin or eyes, or tiredness or loss of appetite, call your doctor.Interferon beta-1a can cause some people to have suicidal thoughts. Be alert for any changes in mood or symptoms. Notify your doctor of any symptoms that are new or getting worse.Tell your doctor before using Avonex if any of the following conditions exist: you are allergic or have a drug allergy; you suffer from liver disease or another disease that causes anaemia; you experience chest pains (angina); you have congestive cardiac failure or heart rhythm disorders; you've had a previous history of depression; or you may be suicidal.

Before you take this drug

Avonex should be avoided if the user is allergic to albumin, natural interferon beta (or recombinant), or natural interferon.

Tell your doctor about any of the following to ensure that Avonex will be safe for you:

  • Mental illness or thoughts of suicide;
  • Liver disease
  • Blood clots or bleeding issues;
  • Low blood cell counts
  • Heart disease
  • A thyroid condition;
  • A latex allergy;
  • An autoimmune disease such as rheumatoid arthritis or lupus.
  • A seizure;
  • If you are a heavy drinker of alcohol,

Some interferon brands contain human plasma that may be contaminated with viruses and other infectious agents. Plasma donated is treated and tested to minimise the chance of contamination. However, there's still a tiny possibility that it can transmit disease. You should ask your doctor if there are any risks.Inform your doctor of any pregnancy or breastfeeding plans.Anyone younger than the age of 18 is not allowed to use Interferon beta-1a.

How to take Avonex?

Follow the instructions on your prescription label and read all medication guides or instruction sheets. Read all the instructions and directions that come with your medication. Sometimes your doctor will change the dose.Avonex can be administered by injection. You may be taught how to use Avonex by your healthcare provider.Please read and follow all instructions for use that come with your medication. If you do not understand, seek assistance from either your pharmacist or doctor.Avonex injections are usually given once a week at night, on the same day every week.Before using the powder, it must first be mixed with a liquid. Only prepare an injection when you're ready to administer it. If the colour of your medicine changes or if it contains particles, do not se it. For new medication, call your pharmacist.You will be shown by your care provider where to inject Avonex. Each time, inject in a new place. Don't inject in the same spot twice.Check for redness or swelling in the area of your injection about 2 hours later. If you notice a reaction to the skin that doesn't go away in a couple of days, call your doctor.You may experience flu-like symptoms when first using this medicine. Other medications may be prescribed to prevent symptoms. Continue to take these medications as prescribed by your doctor.Medical tests will be required frequently.The prefilled syringes or injection pens are only for one-time use. After one usage, throw it out, even if the medicine is still inside.Keep this medication in the fridge. Do not expose yourself to light.Mix the Avonex powder (single-use vial) and a diluteant in the refrigerator. Use the mixture within six hours.Remove the Avonex syringe from the fridge 30 minutes prior to your injection so that it can reach room temperature. The medicine should not be heated in hot water.

Avonex can be stored for a brief period at room temperature, protected from light.

  • The prefilled syringe should not be left out in the refrigerator for more than seven days.
  • Avonex should not be left out of the refrigerator for longer than 30 days.

Don't freeze. Do not freeze.Every vial and syringe has a single use. After one use, throw it out, even if the medicine is still inside.Only use a needle or syringe once, and place it in the "sharps container" to prevent punctures. Be sure to follow local or state laws on how you should dispose of the container. It should be kept out of the reach of pets and children.

What happens if I miss the dose?

Do not use Avonex for two consecutive days. Never use more than one dose at a time.

What happens if I overdose?

Call 1-800-222-1222 for poison help or seek immediate medical attention.

Avoid this

Avonex should not be injected into red or irritated skin.

Side effects of Avonex

If you experience signs of severe allergic reactions to Avonex, such as hives, itching or anxiety, or swelling on your face, throat, or nose, or skin reactions (fever or sore throat with burning eyes or skin, or skin irritation, blisters, and skin peeling), seek emergency medical attention.Interferon beta-1a may cause dangerous blood clots inside the blood vessels of your organs, such as the brain and kidneys. If you experience symptoms such as fever, fatigue, reduced urination, or nosebleeds, seek medical attention immediately.

If you experience:

  • Pain, swelling, bruises, redness, or changes in the skin where the injection has been given
  • A feeling of lightheadedness, as if you could pass out.
  • Unusual changes in behaviour or mood (a feeling of hopelessness, anxiety, nervousness, irritation, or depression);
  • Thoughts of suicide or harming yourself
  • Easy bruising and unusual bleeding
  • A seizure;
  • Heart problems: swelling, rapid growth in weight, shortness of breath, heartbeats that are rapid, pain spreading from your chest to the jaw and shoulder, nausea or sweating,
  • Liver problems: nausea, fatigue, confusion, easy bleeding or bruising, dark urine or clay-coloured stool, or jaundice: yellowing of the skin or eyes;
  • Symptoms of an infection: fever, chills, and a mucousy cough. Diarrhoea: pain, burning, or discomfort when you go to the toilet.
  • Dry skin. Thinning hair, menstrual changes, weight changes, puffiness on your face, and feeling more sensitive to hot or cold temperatures

Avonex may cause side effects such as:

  • Low blood cell counts
  • Skin changes at the site of the injection
  • Depression;
  • Abnormal liver function tests
  • Stomach pain;
  • Flu symptoms include fatigue, weakness, backache, headaches, fever, and chills.

There may be other side effects. For medical advice on side effects, call your doctor. Report any adverse reactions by calling the FDA's Help Line at 1-800-FDA-1088.

Details on dosage

Adult dose for multiple sclerosis:

Once a week, 30 mcg IM:
Titration dose for reducing the severity and incidence of influenza-like symptoms
Week 1: Once a week, 7.5 mcg of IM
Week 2: Once a week, 15 mcg of IM
Week 3: Once a week, 22.5 mcg of IM
Weeks 4+: Once a week, 30 mcg by IM
Patients with relapsing multiple sclerosis can use this drug to reduce the number of exacerbations and slow down the progression of disability. Patients with multiple sclerosis who are shown to be efficacious include those with a clinical episode, MRI findings consistent with MS, and a history of relapse.

Interaction with other drug

Interferon beta-1a may also interact with other drugs, such as prescription or over-the-counter medications, vitamins, and herbal products. Inform your doctor of all the medicines you are taking and those that you stop or start using.