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Generic name: peginterferon alfa-2bpeg-in-ter-FEER-on-AL-fa-too-bee ]
Drug classes: Antineoplastic interferons, Antiviral interferons

Medically reviewed by Philip Thornton, DipPharm. Last updated on Aug 2, 2023.

What is PegIntron?

PegIntron is made from human proteins that help the body fight viral infections.

PegIntron is used in combination with ribavirin (Rebetol, Ribasphere) or other medications to treat chronic hepatitis C in adults and children who are at least 3 years old.

It is not known if PegIntron 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.


You should not use PegIntron with ribavirin if you are pregnant, or if you are a man whose sex partner is pregnant. Use effective birth control to prevent pregnancy while taking ribavirin and for at least 6 months after your last dose.

Peginterferon alfa-2b may cause serious or fatal side effects.

Tell your doctor about any new or worsening mood symptoms, such as feeling irritable, hostile, aggressive, depressed, or having thoughts about suicide or hurting yourself.

Call your doctor right away if you have symptoms such as chest pain, fast heartbeats, trouble breathing, numbness or weakness, vision or speech problems, fever, chills, a cough with mucus, burning when you urinate, or bloody diarrhea.

Before taking this medicine

You should not use PegIntron if:

When taking PegIntron with other medicine: To make sure all medicines are safe for you, tell your doctor about all your medical conditions, and if you are pregnant or breastfeeding.

You should not use PegIntron with ribavirin if you are pregnant, or if you are a man and your sexual partner is pregnant.

PegIntron can worsen a medical condition you already have. To make sure PegIntron is safe for you, tell your doctor if you have ever had:

You may need to have a negative pregnancy test before starting this treatment.

PegIntron is sometimes used in combination with ribavirin. Both men and women using ribavirin should use effective birth control to prevent pregnancy. Ribavirin can cause birth defects, miscarriage, or death to an unborn baby if the mother or father is using this medicine.

You should not take ribavirin if you are pregnant, or if you are a man and your sex partner is pregnant. Use effective birth control to prevent pregnancy. Keep using birth control for at least 6 months after your last dose of ribavirin.

Tell your doctor right away if a pregnancy occurs while either the mother or the father is using ribavirin.

PegIntron may affect fertility (ability to have children) in women. However, it is important to use birth control to prevent pregnancy because peginterferon alfa-2b can harm an unborn baby.

It may not be safe to breastfeed while using PegIntron. Ask your doctor about any risk.

How should I use PegIntron?

Use PegIntron exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. PegIntron is often used with other medicines.

PegIntron is injected under the skin, usually once per week. A healthcare provider may teach you how to properly use the medication by yourself.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you don't understand all instructions.

Prepare a PegIntron injection only when you are ready to give it. Do not use if the medicine looks cloudy, has changed colors, or has particles in it. Call your pharmacist for new medicine.

Your doctor may recommend you take a fever-reducer medication at bedtime to help prevent flu-like symptoms. Use this medicine for as long as your doctor has prescribed.

Pay special attention to your dental hygiene and have regular dental exams while using PegIntron. Rinse your mouth well if you vomit at any time while using PegIntron.

You may need frequent medical tests.

Store PegIntron vials (bottles) in their original package at room temperature, away from moisture and heat. Do not freeze. Do not reuse a vial or injection Redipen.

Store the injection Redipen in a refrigerator. Do not freeze. Mixed medicine may also be stored in the refrigerator but you must use it within 24 hours after mixing. Do not freeze or save any unused mixture.

Each injection Redipen is for one use only. Throw it away after one use, even if there is still medicine left inside.

Use a needle and syringe only once and then place them in a puncture-proof "sharps" container. Follow state or local laws about how to dispose of this container. Keep it out of the reach of children and pets.

What happens if I miss a dose?

Call your doctor for instructions if you miss a dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include headache, extreme tiredness, muscle pain, fever, sore throat, trouble breathing, bruising or bleeding.

What should I avoid while using PegIntron?

Avoid coffee, tea, energy drinks, or other products that contain caffeine.

Using this medicine will not prevent you from passing hepatitis to other people. Follow your doctor's instructions about how to avoid passing the disease to another person.

PegIntron side effects

Get emergency medical help if you have signs of an allergic reaction to PegIntron: hives, or a rash that spreads and causes blistering and peeling; chest pain, anxiety, difficult breathing; swelling of your face, lips, tongue, or throat.

Tell your doctor right away if you have unusual changes in mood or behavior, such as: depression, irritability, feeling hostile or aggressive, hallucinations, thoughts about hurting yourself, or falling back into a previous pattern of drug addiction. These symptoms may occur during treatment and up to 6 months after your last dose.

PegIntron may cause serious or fatal side effects. Call your doctor at once if you have:

Combination treatment with PegIntron and ribavirin can affect growth in children. Tell your doctor if you think your child is not growing at a normal rate while using this combination.

Common PegIntron side effects may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect PegIntron?

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Other drugs may interact peginterferon alfa-2b, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use PegIntron only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.