Peginterferon Beta-1A Injection


Peginterferon beta-1a injection is used to treat adults with various forms of multiple sclerosis (MS; a disease in which the nerves do not function properly and people may experience weakness, numbness, loss of muscle coordination, and problems with vision, speech, and bladder control) including the following:

  • clinically isolated syndrome (CIS; nerve symptom episodes that last at least 24 hours),
  • relapsing-remitting forms (course of disease where symptoms flare up from time to time), or
  • secondary progressive forms (course of disease where relapses occur more often).

Peginterferon beta-1a injection is in a class of medications called immunomodulators. It works by decreasing inflammation and preventing nerve damage that may cause symptoms of multiple sclerosis.

Side Effects Of Peginterferon Beta-1A Injection

Peginterferon beta-1a injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • headache
  • muscle or joint pain
  • fever
  • chills
  • weakness

Some side effects can be serious. If you experience any of these symptoms call your doctor immediately or get emergency medical treatment:

  • yellowing of the skin or eyes
  • dark urine
  • pale stool
  • nausea
  • vomiting
  • loss of appetite
  • unusual bruising or bleeding
  • excessive tiredness
  • confusion
  • irritability
  • nervousness
  • feeling hopeless or bad about yourself
  • thinking about harming or killing yourself or planning or trying to do so
  • seizures
  • shortness of breath
  • pale skin
  • fast or abnormal heartbeat
  • chest pain
  • rash
  • hives
  • itching
  • swelling of the eyes, face, mouth, tongue, throat, hands, arms, feet, ankles, or lower legs
  • hoarseness
  • difficulty breathing or swallowing
  • redness, warmth, swelling, pain, or infection in the place where you injected the medication that does not heal within a few days
  • red or bloody stools or diarrhea
  • stomach pain
  • slow or difficult speech
  • purple patches or pinpoint dots (rash) on the skin
  • decreased urination or blood in the urine

Peginterferon beta-1a injection may cause other side effects. Call your doctor if you have any unusual problems while receiving this medication.

Warnings & Precautions

Before injecting peginterferon beta-1a injection:

  • tell your doctor and pharmacist if you are allergic to peginterferon beta-1a injection, other interferon beta medications (Avonex, Betaseron, Extavia, Rebif), any other medications, or any of the ingredients in peginterferon beta-1a injection. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
  • tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • tell your doctor if you have or have ever had seizures; a mental illness such as depression, especially if you have ever thought about killing yourself or tried to do so; bleeding problems; low numbers of any type of blood cell; or heart, liver, thyroid, or kidney disease.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking peginterferon beta-1a injection, call your doctor.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking peginterferon beta-1a injection.

Dosage Of Peginterferon Beta-1A Injection

  • Peginterferon beta-1a injection comes as a solution (liquid) in a dosing pen or a prefilled syringe to inject subcutaneously (under the skin). It is usually injected once every 14 days. Inject peginterferon beta-1a injection at around the same time of day each time you inject it. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Use peginterferon beta-1a injection exactly as directed. Do not inject more or less of it or inject it more often than prescribed by your doctor.
  • Your doctor will probably start you on a low dose of peginterferon beta-1a injection so that your body can adjust to the medication. You will probably receive a starter pack of peginterferon beta-1a injections that contains two syringes with two different lower doses of medication to use for your first two doses.
  • Peginterferon beta-1a injection may help to control multiple sclerosis but does not cure it. Continue to use peginterferon beta-1a injection even if you feel well. Do not stop using peginterferon beta-1a injection without talking to your doctor.
  • You can inject peginterferon beta-1a yourself, or you can have a friend or relative inject the medication. Read the manufacturer’s directions carefully before you inject the medication for the first time. Ask your doctor or pharmacist to show you how to inject the medication.
  • Use a new prefilled syringe or dosing pen each time you inject your medication. Do not reuse or share syringes or pens. Dispose of used syringes or pens in a puncture-resistant container that is out of the reach of children. Talk to your doctor or pharmacist about how to dispose of the puncture-resistant container.
  • Before you are ready to inject peginterferon beta-1a, you will need to remove the medication from the refrigerator and allow it to rest for around 30 minutes so that it can warm to room temperature. Do not try to warm the medication by heating it in a microwave, placing it in hot water, or through any other method.
  • Always look at the medication in your prefilled syringe or pen before you use it. It should be clear and colorless but may have small air bubbles. If the medication is cloudy, colored, or contains particles or if the expiration date marked on the pen or syringe has passed, do not use that pen or syringe. If you are using a pen, also check to be sure that there are green stripes in the injection status window. Do not use the pen if it does not have green stripes in the injection status window.
  • You can inject peginterferon beta-1a anywhere on your stomach, the back of your upper arms, or your thighs. Choose a different spot each time you inject your medication. Do not inject your medication into the skin that is irritated, bruised, reddened, infected, or scarred.
  • You may experience flu-like symptoms such as headaches, bone or muscle aches, fever, chills, and tiredness during your treatment with peginterferon beta-1a. You should drink plenty of water during your treatment to help prevent or control these symptoms. Your doctor may tell you to take a nonprescription medication that relieves pain and prevents fever before or after you inject your medication to help treat or prevent these symptoms. Talk to your doctor about which other medication(s) you should take during your treatment.


Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body’s response to peginterferon beta-1a injection.

Do not let anyone else use your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.


All information has been provided courtesy of MedLinePlus from the National Library of Medicine and from the FDA.