Peginterferon Alfa-2A Injection


Peginterferon alfa-2a is used alone or in combination with other medications to treat chronic (long-term) hepatitis C infection (swelling of the liver caused by a virus) in people who show signs of liver damage. Peginterferon alfa-2a is also used to treat chronic hepatitis B infection (swelling of the liver caused by a virus) in people who show signs of liver damage.

Peginterferon alfa-2a is in a class of medications called interferons. Peginterferon is a combination of interferon and polyethylene glycol, which helps the interferon stay active in your body for a longer period of time. Peginterferon works by decreasing the amount of hepatitis C virus (HCV) or hepatitis B virus (HBV) in the body. Peginterferon alfa-2a may not cure hepatitis C or hepatitis B or prevent you from developing complications of hepatitis C or hepatitis B such as cirrhosis (scarring) of the liver, liver failure, or liver cancer. Peginterferon alfa-2a may not prevent the spread of hepatitis C or hepatitis B to other people.

Side Effects Of Peginterferon Alfa-2A Injection

Peginterferon alfa-2a may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • bruising, pain, redness, swelling, or irritation in the place you injected peginterferon alfa-2a
  • upset stomach
  • vomiting
  • heartburn
  • dry mouth
  • loss of appetite
  • weight loss
  • diarrhea
  • dry or itchy skin
  • hair loss
  • difficulty falling asleep or staying asleep
  • tiredness
  • weakness
  • difficulty concentrating or remembering
  • sweating
  • dizziness

Some side effects can be serious. The following symptoms are uncommon, but if you experience any of them or those listed in the WARNINGS and PRECAUTIONS section, call your doctor immediately:

Peginterferon alfa-2a may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

Warnings & Precautions

Before using peginterferon alfa-2a:

  • tell your doctor and pharmacist if you are allergic to peginterferon alfa-2a, other alpha interferons, any other medications, benzyl alcohol, or polyethylene glycol (PEG). Ask your doctor if you are not sure if a medication you are allergic to is alpha interferon.
  • tell your doctor if you have ever received an interferon alfa injection for treating hepatitis C infection.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: certain medications for HIV or AIDS such as abacavir (Ziagen, in Epzicom, in Trizivir), didanosine (ddI or Videx), emtricitabine (Emtriva, in Truvada), lamivudine (Epivir, in Combivir, in Epzicom, in Trizivir), stavudine (Zerit), tenofovir (Viread, in Truvada), zalcitabine (HIVID), and zidovudine (Retrovir, in Combivir, in Trizivir); methadone (Dolophine, Methadose); mexiletine (Mexitil); naproxen (Aleve, Anaprox, Naprosyn, others); riluzole (Rilutek); tacrine (Cognex); telbivudine (Tyzeka); and theophylline (TheoDur, others). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with peginterferon alfa-2a, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
  • tell your doctor or pharmacist if you have ever had an organ transplant (surgery to replace an organ in the body). Also tell your doctor if you have or have ever had any of the conditions mentioned in the WARNINGS and PRECAUTIONS section or any of the following: anemia (red blood cells do not bring enough oxygen to other parts of the body), or problems with your eyes or pancreas.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. Peginterferon alfa-2a may harm the fetus or cause you to miscarry (lose your baby). Talk to your doctor about using birth control while you are taking this medication. You should not breastfeed while you are taking this medication.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking peginterferon alfa-2a.
  • you should know that peginterferon alfa-2a may make you dizzy, confused, or drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
  • do not drink alcohol while you are taking peginterferon alfa-2a. Alcohol can make your liver disease worse.
  • you should know that you may experience flu-like symptoms such as headache, fever, chills, tiredness, muscle aches, and joint pain during your treatment with peginterferon alfa-2a. If these symptoms are bothersome, ask your doctor if you should take an over-the-counter pain and fever reducer before you inject each dose of peginterferon alfa-2a. You may want to inject peginterferon alfa-2a at bedtime so that you can sleep through the symptoms.

Dosage Of Peginterferon Alfa-2A Injection

Peginterferon alfa-2a comes as a solution (liquid) in a vial, a prefilled syringe, and a disposable autoinjector to inject subcutaneously (into the fatty layer just under the skin). It is usually injected once a week, on the same day of the week, and at around the same time of day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Use peginterferon alfa-2a exactly as directed. Do not use more or less of this medication or use it more often than prescribed by your doctor.

Your doctor will probably start you on an average dose of peginterferon alfa-2a. Your doctor may decrease your dose if you experience serious side effects of the medication. Be sure to tell your doctor how you are feeling during your treatment and ask your doctor or pharmacist if you have questions about the amount of medication you should take.

Continue to use peginterferon alfa-2a even if you feel well. Do not stop using peginterferon alfa-2a without talking to your doctor.

Only use the brand and type of interferon that your doctor prescribed. Do not use another brand of interferon or switch between peginterferon alfa-2a in vials, prefilled syringes, and disposable autoinjectors without talking to your doctor. If you switch to a different brand or type of interferon, your dose may need to be changed.

You can inject peginterferon alfa-2a yourself or have a friend or relative give you the injections. Before you use peginterferon alfa-2a for the first time, you and the person who will be giving the injections should read the manufacturer’s information for the patient that comes with it. Ask your doctor or pharmacist to show you or the person who will be injecting the medication how to inject it. If another person will be injecting the medication for you, be sure that he or she knows how to avoid accidental needlesticks to prevent the spread of hepatitis.

You can inject peginterferon alfa-2a anywhere on your stomach or thighs, except your navel (belly button) and waistline. Use a different spot for each injection. Do not use the same injection spot two times in a row. Do not inject peginterferon alfa-2a into an area where the skin is sore, red, bruised, scarred, infected, or abnormal in any way.

If you do not receive the full prescribed dose because of a problem (such as leakage around the injection site), call your doctor.

Never reuse syringes, needles, or vials of peginterferon alfa-2a. Dispose of used needles and syringes in a puncture-resistant container. Talk to your doctor or pharmacist about how to dispose of the puncture-resistant container.

Before you use peginterferon alfa-2a, look at the solution in the vial, prefilled syringe, or autoinjector closely. Do not shake vials, syringes, or autoinjectors containing peginterferon alfa-2a. The medication should be clear and free of floating particles. Check the vial or syringe to make sure there are no leaks and check the expiration date. Do not use the solution if it is expired, discolored, cloudy, contains particles, or is in a leaky vial or syringe. Use a new solution, and show the damaged or expired one to your doctor or pharmacist.


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.