Peginterferon alfa-2b is made from human proteins that help the body fight viral infections.

Peginterferon alfa-2b is used to treat chronic hepatitis C in adults. Peginterferon alfa-2b is often used in combination with another medication called ribavirin (Copegus, Rebetol, RibaPak, Ribasphere, RibaTab) to treat hepatitis C in adults and children who are at least 3 years old.

Peginterferon alfa-2b may be used in combination with boceprevir (Victrelis) or telaprevir (Incivek) to treat hepatitis C in adults.

The Sylatron brand of peginterferon alfa-2b is used to treat melanoma (skin cancer) after surgery.

Peginterferon alfa-2b may also be used for purposes not listed in this medication guide.

You should not use peginterferon alfa-2b if you are allergic to it, or if you have autoimmune hepatitis, severe liver or kidney disease, or a hemoglobin blood cell disorder such as sickle-cell anemia or thalassemia.

Peginterferon alfa-2b is often used together with another medication called ribavirin (Copegus, Rebetol, RibaPak, Ribasphere, RibaTab), which is known to cause birth defects or death in an unborn baby. Do not use peginterferon alfa-2b and ribavirin if you are pregnant, or if you are a man and your female sexual partner is pregnant.

Before using peginterferon alfa-2b, tell your doctor about all of your medical conditions, especially kidney disease, liver problems other than hepatitis, heart disease or high blood pressure, a thyroid disorder, eye problems, HIV or AIDS, ulcerative colitis, a blood cell disorder, an autoimmune disorder such as lupus or psoriasis, or a history of heart attack, stroke, organ transplant, depression, mental illness, drug or alcohol addiction, or suicidal thoughts or behaviors.

Stop using peginterferon alfa-2b and call your doctor at once if you have severe or worsening symptoms such as: confusion, depression, tired feeling, anxiety, aggression, tremors, muscle twitching, seizure, unusual thoughts or behavior, or thoughts about suicide or hurting yourself. Once you have had this type of reaction to peginterferon alfa-2b, you must never use it again.

There are many other medicines that can interact with peginterferon alfa-2b. Tell your doctor about all the prescription and over-the-counter medications you use.

You should not use this medication if you are allergic to peginterferon alfa-2b, or if you have:

• autoimmune hepatitis;

• liver failure;

• severe kidney disease;

• a hemoglobin blood cell disorder such as sickle-cell anemia or thalassemia;

• if you are pregnant; or

• if you are a man and your female sexual partner is pregnant.

To make sure you can safely use peginterferon alfa-2b, tell your doctor if you have any of these other conditions:

• lung disease;

• kidney disease (or if you are on dialysis);

• hepatitis B, or liver problems other than hepatitis;

• a thyroid disorder;

• uncontrolled diabetes;

• new or worsening problems with your eyes;

• cancer;

• HIV or AIDS;

• pancreatitis or ulcerative colitis;

• heart disease, high blood pressure, high cholesterol or triglycerides, or a history of heart attack, or stroke;

• dental problems or gum disease;

• an allergy causing severe reaction;

• history of organ transplant;

• anemia (low red blood cells) caused by taking ribavirin (Rebetol);

• any blood cell disorder causing bleeding episodes, infections, or fever-related illness;

• an autoimmune disorder such as rheumatoid arthritis, systemic lupus erythematosus (SLE), or psoriasis; or

• a history of drug or alcohol addiction, depression, anxiety, or suicidal thoughts or behaviors.

Peginterferon alfa-2b may be harmful to an unborn baby. Do not use peginterferon alfa-2b without telling your doctor if you are pregnant.

Peginterferon alfa-2b is often used together with another medication called ribavirin (Copegus). Ribavirin is known to cause birth defects or death in an unborn baby. You may need to have a negative pregnancy test before taking these two medications together and every month during your treatment.

• If you are a woman, do not use peginterferon alfa-2b and ribavirin if you are pregnant.

• If you are a man, do not use peginterferon alfa-2b and ribavirin if your female sexual partner is pregnant. An unborn baby could also be harmed if a man fathers the child while he is taking ribavirin.

• Use at least 2 effective forms of birth control while either sexual partner is using peginterferon alfa-2b with ribavirin. Keep using 2 forms of birth control for at least 6 months after treatment ends.

• Tell your doctor right away if a pregnancy occurs while either the mother or the father is using peginterferon alfa-2b together with ribavirin.

It is not known whether peginterferon alfa-2b passes into breast milk or if it could harm a nursing baby. You should not breast-feed while you are using peginterferon alfa-2b.

Peginterferon alfa-2b can affect growth in children. Talk with your doctor if you think your child is not growing at a normal rate while using this medication.