Health Guide

Interferon Alfa-2a (Injection)

Interferon Alfa-2a (in-ter-FEER-on AL-fa-2a)

Treats hepatitis C and certain types of leukemia (hairy cell leukemia and Philadelphia chromosome positive chronic myelogenous leukemia (CML)). This product was withdrawn from the U.S. market on October 1, 2007.

Brand Name(s):

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not receive this medicine if you have had an allergic reaction to interferon alfa-2a or to benzyl alcohol, or if you have ever had autoimmune hepatitis or other severe liver problems, or if you have a weakened immune system. This medicine should not be given to infants.

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.
  • This medicine should come with a Medication Guide. Read and follow these instructions carefully. Ask your doctor or pharmacist if you have any questions. Ask your pharmacist for the Medication Guide if you do not have one. Your doctor might ask you to sign some forms to show that you understand this information.
  • A nurse or other trained health professional 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.
  • This medicine comes with patient instructions. Read and follow these instructions carefully. Ask your doctor or pharmacist if you have any questions.
  • Use only the brand of this medicine that your doctor prescribed. Different brands may not work the same way. Switching brands will also require a change in your dose.
  • 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.
  • Use a new needle and syringe each time you inject your medicine.

If a dose is missed:

  • If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

  • If you store this medicine at home, keep it in the refrigerator. Do not freeze. Do not shake the syringe.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any leftover medicine, containers, and other supplies. You will also need to throw away old medicine after the expiration date has passed.
  • Throw away used needles in a hard, closed container that the needles cannot poke through. Keep this container away from children and pets.
  • Keep all medicine away from children and never share your medicine with anyone.

Drugs and Foods to Avoid:

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

  • Make sure your doctor knows if you are using theophylline (Theo-Dur®), zidovudine (Retrovir®), or medicines that weaken the immune system (such as steroids, drugs used after an organ transplant, or certain cancer drugs).
  • Tell your doctor if you are using any medicines that make you sleepy. These include sleeping pills, cold and allergy medicine, narcotic pain relievers, and sedatives.
  • Talk to your doctor before getting flu shots or other vaccines while you are receiving this medicine. Vaccines may not work as well, or they could make you ill while you are using this medicine.

Warnings While Using This Medicine:

  • Make sure your doctor knows if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, seizures, lung disease or breathing problems, heart disease or a history of heart attack, diabetes, thyroid problems, autoimmune disease (such as arthritis or lupus), herpes simplex, a history of depression, bleeding problems, sleeping problems, vision problems, or if you have a weakened immune system or have had a head injury or an organ transplant. Tell your doctor if you have a history of mental illness, or if you have been addicted to drugs or alcohol.
  • This medicine can cause mood or behavioral problems (getting easily upset, feeling low, feeling bad about yourself or feeling hopeless). It can also increase thoughts of suicide. Tell your doctor right away if you start to feel more depressed. Also tell your doctor right away if you have thoughts about hurting yourself or others. Make sure your caregiver knows if you have trouble sleeping, get upset easily, feeling nervous, angry, restless, violent, or scared, or have a big increase in energy. Report any unusual thoughts or behaviors that trouble you, especially if they are new or get worse quickly. Let your doctor know if you or anyone in your family has bipolar disorder (manic-depressive) or has tried to commit suicide.
  • This medicine lowers the number of some types of blood cells in your body. Because of this, you may bleed or get infections more easily. To help with these problems, avoid being near people who are sick or have infections. Wash your hands often. Stay away from rough sports or other situations where you could be bruised, cut, or injured. Brush and floss your teeth gently. Be careful when using sharp objects, including razors and fingernail clippers.
  • If you have severe diarrhea, ask your doctor before taking any medicine to stop the diarrhea.
  • Tell your doctor right away if you start having sudden and severe stomach pain, nausea, or vomiting. You may already be having problems with your pancreas.
  • Check with your doctor immediately if blurred vision, difficulty in reading, or any other change in vision occurs during or after treatment. Your doctor may want you to have your eyes checked by an eye doctor.
  • This medicine may affect blood sugar levels. If you notice a change in the results of your blood or urine sugar tests, or if you have any questions, check with your doctor.
  • Your doctor will need to check your blood or urine at regular visits while you are using this medicine. Be sure to keep all appointments.
  • This medicine may make you dizzy or drowsy. Avoid driving, using machines, or doing anything else that could be dangerous if you are not alert.

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.
  • Chest pain or tightness.
  • Dark-colored urine or pale stools.
  • Fast or irregular heartbeat.
  • Fever, chills, cough, sore throat, stuffy or runny nose.
  • Lightheadedness, dizziness, or fainting.
  • Nausea, vomiting, loss of appetite, pain in the upper or lower stomach.
  • Numbness or weakness in your arm or leg, or on one side of your body.
  • Numbness, tingling, or a cold feeling in your hands or feet.
  • Painful urination, or decrease in how much or how often you urinate.
  • Problems with vision.
  • Seizures.
  • Severe irritability, anxiety, depression, thoughts of hurting yourself, or others mood or behavior changes.
  • Shortness of breath, cold sweat, and bluish-colored skin.
  • Swelling in your hands, ankles, or feet.
  • Unusual bleeding or bruising.
  • Unusual tiredness or weakness.
  • Yellow skin or eyes.

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

  • Back pain.
  • Diarrhea.
  • Dry skin, or skin rash or itching.
  • Headache, confusion.
  • Increased sweating.
  • Mild irritability, anxiety, or trouble sleeping.
  • Muscle, bone, or joint pain.
  • Pain, itching, burning, swelling, or a lump under your skin where the shot is given.
  • Partial hair loss.
  • Swollen joints.
  • Weight loss.

Last Updated: 6/12/2013
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