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Peginterferon Alfa-2b (By injection)

Peginterferon Alfa-2b (peg-in-ter-FEER-on AL-fa-2b)

Treats hepatitis C. Also treats melanoma (skin cancer).

Brand Name(s):

PEGIntron, Sylatron

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. You should not receive it if you had an allergic reaction to peginterferon alfa-2b, or if you have sickle cell anemia or other liver problems (including autoimmune hepatitis).

How to Use This Medicine:


  • Your doctor will prescribe your exact dose and tell you how often it should be given. This medicine is given as a shot under your skin.
  • A nurse or other health provider will give you this medicine.
  • You may be taught how to give your medicine at home. Make sure you understand all instructions before giving yourself an injection. Do not use more medicine or use it more often than your doctor tells you to.
  • Check the medicine in the pen or vial. It should look like a white to off-white tablet that is whole, or in pieces, or powdered. Gently swirl the pen or vial after adding water in it. Do not use the medicine if it is cloudy, discolored, or has particles in it. Do not shake.
  • You will be shown the body areas where this shot can be given. Use a different body area each time you give yourself a shot. Keep track of where you give each shot to make sure you rotate body areas. Do not inject into skin areas that are red, bruised, irritated, or infected, or have scars, stretch marks, or lumps.
  • You may take fever medicine (including acetaminophen) 30 minutes before using this medicine to prevent flu-like symptoms. Drink plenty of fluids.
  • Use the pen or vial only one time. Throw away any leftover medicine.
  • Use a new needle and syringe each time you inject your medicine.
  • Use only the brand of medicine your doctor prescribed. Other brands may not work the same way.
  • This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.
  • Missed dose:
    • For patients with hepatitis C: Use a dose as soon as you remember if it is the same day or the next day. Then go back to your regular dosing schedule. If it has been several days since you have missed your dose, call your doctor or pharmacist for instructions. Do not use more than one injection in a week.
    • For patients with melanoma: Call your doctor or pharmacist for instructions.
  • PegIntron®: Store the Redipen® prefilled pen in the refrigerator and the vial at room temperature. If the powder medicine cannot be used right after it is mixed, it may be kept in the refrigerator and used within 24 hours. Do not freeze the powder or the mixture.
  • Sylatron™: Store the vial at room temperature. If the powder medicine cannot be used right after it is mixed, it may be kept in the refrigerator and used within 24 hours. Do not freeze the mixture.
  • Throw away used needles in a hard, closed container that the needles cannot poke through. Keep this container away from children and pets.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Some foods and medicines can affect how peginterferon alfa-2b works. Tell your doctor if you are using any of the following:
    • Cyclosporine, desipramine, methadone, sirolimus, tacrolimus, telbivudine, theophylline, thioridazine
    • Medicine to treat HIV or AIDS (including didanosine, lamivudine, stavudine, zidovudine)
  • Tell your doctor if you drink caffeinated beverages, including coffee or cola.

Warnings While Using This Medicine:

  • Pregnancy:
    • PegIntron®:
      • Using this medicine alone or in combination with ribavirin while you are pregnant can harm your unborn baby. Women should use an effective form of birth control during treatment and for 6 months after the last dose. Female partners of male patients should also use an effective form of birth control during treatment and for 6 months after the last dose.
      • Female patients must have regular pregnancy tests during treatment with this medicine together with ribavirin and for 6 months after stopping treatment.
    • Sylatron™: It is not safe to take this medicine during pregnancy. It could harm an unborn baby. Tell your doctor right away if you become pregnant. Use an effective form of birth control during treatment with this medicine and for at least 10 days after the last dose.
  • Tell your doctor if you are breastfeeding, or if you have kidney disease, other liver diseases, bleeding problems, lung problems (including COPD), heart or blood vessel disease, heart rhythm problems, diabetes, thyroid problems, or an autoimmune disorder (including psoriasis, lupus, or arthritis). Tell your doctor if you have a history of heart attack, stroke, depression, or drug abuse. Also tell your doctor if you had an organ transplant.
  • This medicine may increase mental or emotional problems. This may lead to thoughts of suicide and violence. Talk with your doctor right away if you have any thoughts or behavior changes that concern you. Tell your doctor if you or anyone in your family has a history of bipolar disorder or suicide attempts.
  • This medicine may cause the following problems:
    • Heart rhythm problems or other heart or blood vessel problems (including heart attack or stroke)
    • New or worsening diabetes, thyroid problems, or autoimmune disorders
    • New or worsening lung or liver problems
    • Pancreatitis (swelling of the pancreas)
    • Vision changes or eye problems
    • Serious allergic and skin reactions
    • High cholesterol in the blood
    • Slowed growth in children
    • Peripheral neuropathy (nerve problem)
  • This medicine may make you bleed, bruise, or get infections more easily. Take precautions to prevent illness and injury. Wash your hands often.
  • This medicine can cause diarrhea. Call your doctor if the diarrhea becomes severe, does not stop, or is bloody. Do not take any medicine to stop diarrhea until you have talked to your doctor. Diarrhea can occur 2 months or more after you stop taking this medicine.
  • Tell any doctor or dentist who treats you that you are using this medicine. This medicine may affect certain medical test results.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blistering, peeling, or red skin rash
  • Bloody or black, tarry stools
  • Chest pain, coughing up blood, trouble breathing, unusual sweating, lightheadedness, dizziness, or fainting
  • Dark urine or pale stools, loss of appetite, stomach pain, yellow skin or eyes
  • Fast, slow, pounding, or uneven heartbeat
  • Fever, chills, cough, sore throat, body aches
  • Numbness, tingling, or burning pain in your hands, arms, legs, or feet
  • Sudden and severe stomach pain, nausea, vomiting, and fever
  • Sudden or severe headache, problems with walking or talking
  • Unusual bleeding, bruising, or weakness
  • Unusual thoughts or behaviors, depression, thoughts of hurting yourself or others
  • Vision changes, blurred vision, eye pain

If you notice these less serious side effects, talk with your doctor:

  • Dry mouth
  • Hair loss
  • Mild diarrhea, changes in appetite
  • Redness, pain, itching, or bruising where the shot was given

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 5/1/2020

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites.

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