Generic Name: Peginterferon alfa-2a

  • What is Pegasys?

    Pegasys is an antiviral medicine used alone or in combination with Copegus (ribavirin) to treat chronic (long-term) hepatitis C infection. It is also used to treat chronic hepatitis B infection. Pegasys is administered subcutaneously (just below the skin).

  • What is the most important information I should know about Pegasys?

    Pegasys can cause mood or behavioral problems, such as irritability (getting upset easily), depression, aggressive behavior, suicidal thoughts, or thoughts of hurting yourself or others.

    Pegasys can cause heart problems, such as low blood pressure, fast heart rate or abnormal heartbeat, trouble breathing, chest pain, or heart attack.

    Pegasys can cause a stroke or symptoms of a stroke, such as weakness, loss of coordination, and numbness.

    Pegasys can cause new or worsen autoimmune problems (such as rheumatoid arthritis, systemic lupus erythematosus, or psoriasis).

    Pegasys can cause infections. Tell your doctor if you experience fever, chills, bloody diarrhea, burning or pain with urination, frequent urination, or coughing up mucus (phlegm) that is yellow or pink.

    Pegasys can also cause other serious side effects, such as eye problems; pancreatitis (inflammation of the pancreas); colitis (inflammation of the lower bowel); growth problems in children; worsen or cause liver, thyroid, lung, blood, nerve, or blood sugar problems; or allergic and skin reactions.

    Pegasys can affect your bone marrow and cause low white blood cell and platelet (type of blood cells that form clots to help stop bleeding) counts, that can predispose you to infections and problems with bleeding and bruising.

  • Who should not take Pegasys?

    Do not use Pegasys if you are allergic to it or any of its ingredients. Also, do not use Pegasys if you have certain types of hepatitis (such as autoimmune hepatitis) or other liver problems.

    Do not use Pegasys with Copegus if you are pregnant, plan to become pregnant, are a man whose partner is pregnant, have certain blood disorders (such as thalassemia major or sickle-cell anemia), have severe kidney disease, or take didanosine.

  • What should I tell my doctor before I take the first dose of Pegasys?

    Tell your doctor about all prescription, over-the-counter, and herbal medications you are taking before beginning treatment with Pegasys. Also, talk to your doctor about your complete medical history, especially if you have or ever had heart, lung, bleeding, or vision problems; low blood cell counts; certain blood disorders (such as anemia); addiction to drugs or alcohol; any immune problems; liver, kidney, or thyroid problems; colitis; hepatitis B infection; HIV (AIDS) infection; high blood triglyceride levels; mental health problems (such as depression or thoughts of suicide); an organ transplant; or diabetes.

  • What is the usual dosage?

    The information below is based on the dosage guidelines your doctor uses. Depending on your condition and medical history, your doctor may prescribe a different regimen. Do not change the dosage or stop taking your medication without your doctor's approval.

    Adults and children: Your doctor will prescribe the appropriate dose for you based on your condition.

    If you have kidney or liver impairment, depression, or abnormal tests, your doctor will adjust your dose appropriately.

  • How should I take Pegasys?

    Inject Pegasys exactly as prescribed by your doctor. Do not inject extra doses or use more often without asking your doctor.

    Please review the instructions that came with your prescription on how to properly prepare and inject Pegasys.

    Inject Pegasys every week, on the same day of each week, and at the same time.

  • What should I avoid while taking Pegasys?

    Do not become pregnant while you are using Pegasys with Copegus.

    Do not inject more than 1 dose of Pegasys in 1 week without talking to your doctor.

    Do not drink alcohol, including beer, wine, or liquor. This can make your liver disease worse.

  • What are possible food and drug interactions associated with Pegasys?

    If Pegasys is used with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Pegasys with the following: azathioprine, didanosine, HIV medications known as nucleoside analogues (such as lamivudine, stavudine, or zidovudine), methadone, theophylline, or telbivudine.

  • What are the possible side effects of Pegasys?

    Side effects cannot be anticipated. If any develop or change in intensity, tell your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking this drug.

    Side effects may include: allergic reactions, blood disorders, diabetes, difficulty sleeping, fever, hair thinning, headache, loss of appetite, muscle pain, nausea, nerve problems, pancreatitis (inflammation of your pancreas), thyroid problems, tiredness, vision loss, vomiting

  • Can I receive Pegasys if I am pregnant or breastfeeding?

    The effects of Pegasys during pregnancy and breastfeeding are unknown. When Pegasys is used with Copegus, Copegus may cause harm to your unborn baby if you use it during pregnancy. Tell your doctor immediately if you are pregnant, plan to become pregnant, or are breastfeeding.

  • What should I do if I miss a dose of Pegasys?

    If you miss a dose of Pegasys, inject the missed dose as soon as possible during the same day or the next day, and return to your regular dosing schedule. If several days go by after you miss a dose, contact your doctor for advice.

  • How should I store Pegasys?

    Store in the refrigerator. Do not freeze, shake, or leave out of the refrigerator for more than 24 hours. Protect from light.