PegIntron is a prescription medicine that is used:

  • with REBETOL (ribavirin) and an approved hepatitis C virus (HCV) protease inhibitor to treat chronic (lasting a long time) hepatitis C infection in adults.
  • with REBETOL (ribavirin) to treat chronic (lasting a long time) hepatitis C infection in people 3 years and older with stable liver problems.
  • alone, sometimes to treat adults who have chronic (lasting a long time) hepatitis C infection with stable liver problems and who cannot take REBETOL (ribavirin). People with hepatitis C have the virus in their blood and in their liver. PegIntron reduces the amount of virus in the body and helps the body’s immune system fight the virus. REBETOL (ribavirin) is a drug that helps to fight viral infection but does not work when used by itself to treat chronic hepatitis C.

It is not known if use for longer than 1 year is safe and will work.

It is not known if PegIntron use in children younger than 3 years old is safe and will work.

Side Effects Of PegIntron

PegIntron can cause serious side effects that:

  • may cause death, or
  • may worsen certain serious diseases that you may already have.

Tell your healthcare provider right away if you have any of the symptoms listed below while taking PegIntron. If symptoms get worse, or become severe and continue, your healthcare provider may tell you to stop taking PegIntron permanently. In many, but not all, people, these symptoms go away after they stop taking PegIntron.

Mental health problems, including suicide. PegIntron may cause you to develop mood or behavior problems that may get worse during treatment with PegIntron or after your last dose, including:

  • irritability (getting upset easily)
  • depression (feeling low, feeling bad about yourself, or feeling hopeless)
  • acting aggressive, being angry or violent
  • thoughts of hurting yourself or others, or suicide
  • former drug addicts may fall back into drug addiction or overdose

If you have these symptoms, your healthcare provider should carefully monitor you during treatment with PegIntron and for 6 months after your last dose.

Heart problems. Some people who take PegIntron may get heart problems, including:

Stroke or symptoms of a stroke. Symptoms may include weakness, loss of coordination, and numbness. Stroke or symptoms of a stroke may happen in people who have some risk factors or no known risk factors for a stroke.

New or worsening autoimmune problems. Some people taking PegIntron develop autoimmune problems (a condition where the body’s immune cells attack other cells or organs in the body), including rheumatoid arthritis, systemic lupus erythematosus, and psoriasis. In some people who already have an autoimmune problem, it may get worse during your treatment with PegIntron.

Infections. Some people who take PegIntron may get an infection. Symptoms may include:

  • fever
  • chills
  • bloody diarrhea
  • burning or pain with urination
  • urinating often
  • coughing up mucus (phlegm) that is discolored (for example, yellow or pink)

PegIntron in combination with REBETOL (ribavirin) may cause birth defects or the death of your unborn baby. Do not take PegIntron and ribavirin combination therapy if you or your sexual partner are pregnant or plan to become pregnant. Do not become pregnant within 6 months after discontinuing PegIntron and ribavirin combination therapy. You must use 2 forms of birth control when you take PegIntron and ribavirin and for the 6 months after treatment.

• Females must have a pregnancy test before starting PegIntron and ribavirin combination therapy, every month while on the combination therapy, and every month for the 6 months after the last dose of combination therapy.

Warnings & Precautions

Do not take PegIntron:

  • if you have had a serious allergic reaction to another alpha interferon or to any of the ingredients in PegIntron. See the end of this Medication Guide for a complete list of ingredients. Ask your healthcare provider if you are not sure.
  • if you have certain types of hepatitis (autoimmune hepatitis).
  • if you have certain other liver problems.
  • with REBETOL (ribavirin) if you are pregnant, planning to get pregnant, or breastfeeding. Talk to your healthcare provider before taking PegIntron if you have any of these conditions.

Before you take it, tell your healthcare provider if you:

  • are being treated for a mental illness or had treatment in the past for any mental illness, including depression and thoughts of hurting yourself or others
  • have or ever had any problems with your heart, including heart attack or high blood pressure
  • have any kind of autoimmune disease (where the body’s immune system attacks the body’s own cells), such as psoriasis, systemic lupus erythematosus, rheumatoid arthritis
  • have or ever had bleeding problems or a blood clot
  • have or ever had low blood cell counts
  • have ever been addicted to drugs or alcohol
  • have cirrhosis or other liver diseases (other than hepatitis C infection)
  • have or had lung disease such as chronic obstructive pulmonary disease (COPD)
  • have thyroid problems
  • have diabetes
  • have colitis (inflammation of your intestine)
  • have a condition that suppresses your immune system, such as cancer
  • have hepatitis B infection
  • have HIV infection
  • have kidney problems
  • have high blood triglyceride levels (fat in your blood)
  • have an organ transplant and are taking medicine that keeps your body from rejecting your transplant (suppresses your immune system)
  • have any other medical problems
  • are pregnant or plan to become pregnant. PegIntron may harm your unborn baby. You should use effective birth control during treatment with PegIntron. Talk to your healthcare provider about birth control choices for you during treatment with PegIntron. Tell your healthcare provider if you become pregnant during treatment with PegIntron.
  • are breastfeeding or plan to breastfeed. It is not known if PegIntron passes into your breast milk.

You and your healthcare provider should decide if you will use PegIntron or breastfeed.

Tell your healthcare provider about all the medicines you take, including prescription and nonprescription medicines, vitamins, and herbal supplements. PegIntron and certain other medicines may affect each other and cause side effects.

Especially tell your healthcare provider if you take the anti-hepatitis B medicine telbivudine (Tyzeka).

Dosage Of PegIntron

Take PegIntron exactly as your healthcare provider tells you to. Your healthcare provider will tell you how much PegIntron to take and when to take it. Do not take more than your prescribed dose.

  • Take your prescribed dose every week, on the same day of each week and at the same time.
  • PegIntron is given as an injection under your skin (subcutaneous injection). Your healthcare provider should show you how to prepare and measure your dose of PegIntron, and how to inject yourself before you use PegIntron for the first time.
  • You should not inject PegIntron until your healthcare provider has shown you how to use PegIntron the right way.
  • PegIntron comes as a:
    • powder in a single-use vial
    • single-use REDIPEN

Your healthcare provider will prescribe the PegIntron that is right for you. See the Instructions for Use that comes with your PegIntron for detailed instructions for preparing and injecting a dose of PegIntron.

  • If you miss a dose, take the missed dose as soon as possible during the same day or the next day, then continue on your regular dosing schedule. If several days go by after you miss a dose, check with your healthcare provider about what to do.
  • Do not inject more than 1 dose of PegIntron in one week without talking to your healthcare provider.
  • If you take too much PegIntron, call your healthcare provider right away. Your healthcare provider may examine you more closely, and do blood tests.
  • Your healthcare provider should do blood tests before you start PegIntron, and regularly during treatment to see how well the treatment is working and to check you for side effects.


Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Do not use PegIntron for a condition for which it was not prescribed. Do not give PegIntron to other people, even if they have the same symptoms that you have. It may harm them. This Medication Guide summarizes the most important information about PegIntron. If you would like more information, ask your healthcare provider. You can ask your healthcare provider or pharmacist for information about PegIntron that was written for healthcare professionals.


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