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Interferon Alfacon-1 (Injection)

Interferon Alfacon-1 (in-ter-FEER-on AL-fa-kon-1)

Treats hepatitis C infection.

Brand Name(s):


There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have had an allergic reaction to interferon alfa, have serious liver disease, or autoimmune hepatitis (liver inflammation). Do not use this medicine together with ribavirin if you have had an allergic reaction to ribavirin, if you are pregnant, if your female sexual partner is pregnant, if you have a blood disorder (such as sickle cell anemia or thalassemia major), or severe kidney disease.

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.
  • This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.
  • This medicine must be used for the full time of treatment, even if you begin to feel better after a few days or weeks. It is also very important that you receive your injection at the same time of day for each dose.
  • Use each vial (glass container) only one time. If the vial contains extra medicine, throw it away.
  • 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.
  • Use only the brand of medicine your doctor prescribed. Other brands may not work the same way.

If a dose is missed:

  • If you miss a dose or forget to use your medicine, use it as soon as you can and then call your doctor. You must talk to your doctor first before you receive your next scheduled 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.
  • Allow this medicine to reach room temperature before using it. Do not shake the vial or expose it to direct sunlight.
  • Throw away used needles in a hard, closed container that the needles cannot poke through. Keep this container away from children and pets.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any leftover medicine, containers, and other supplies. Throw away old medicine after the expiration date has passed.
  • Keep all medicine out of the reach of children. 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 telbivudine (Tyzeka®) or medicines that weaken your immune system, such as a steroid medicine or cancer treatment.

Warnings While Using This Medicine:

  • Using this medicine together with ribavirin while you are pregnant can harm your unborn baby. The medicine may also cause birth defects if the father is using it when his sexual partner becomes pregnant. If a pregnancy occurs while you are using this medicine, tell your doctor right away.
  • A negative pregnancy test is needed in women who are of childbearing age before starting combination treatment with interferon alfacon-1 and ribavirin. Two forms of birth control must be used during treatment and for six months after treatment ends. You will need to have pregnancy tests done regularly to make sure you are not pregnant while being treated with these medicines and after your treatment ends.
  • Make sure your doctor knows if you are breastfeeding, or if you have kidney disease, liver disease (including cirrhosis, hepatitis B), heart disease, history of a heart attack or stroke, heart rhythm problems, high or low blood pressure, high fats in the blood, bleeding problems, cancer, diabetes, lung or breathing problems (such as chronic obstructive pulmonary disease), vision problems, thyroid disease, or an autoimmune disease (such as psoriasis, arthritis, or systemic lupus erythematosus).
  • Make sure your doctor knows if you have a history of depression, bipolar disorder, HIV or AIDS, or an addiction to drugs or alcohol. Also, tell your doctor if you have had an organ transplant (such as liver or kidney).
  • You might have mood or behavior changes with this medicine, such as feeling sad or hopeless, or getting upset easily. You could feel nervous or hostile. Some people become violent and want to hurt themselves or others. You might have too much energy, or see or hear unusual things. Call your doctor right away if you have any strange feelings, thoughts, or behaviors.
  • This medicine will not keep you from giving hepatitis C to other people.
  • 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.
  • This medicine may cause a serious type of allergic reaction called anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Call your doctor right away if you have a rash; itching; hoarseness; trouble breathing; trouble swallowing; or any swelling of your hands, face, or mouth while you are using this medicine.
  • This medicine may cause flu symptoms such as fever, chills, tiredness, and muscle aches when you first start using it. Using your shot at bedtime may allow you to sleep through the symptoms. Your doctor may want you to take a medicine for pain and fever (such as acetaminophen or ibuprofen) before or after each dose of interferon alfacon-1. Carefully follow your doctor's instructions about how to prevent or treat these symptoms.
  • 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 ophthalmologist (eye doctor).
  • Check with your doctor right away if you are having burning, numbness, tingling, or painful sensations in the arms, hands, legs, or feet. These could be symptoms of a condition called peripheral neuropathy.
  • This medicine may cause high blood sugar levels. If you are diabetic and notice a change in the results of your blood or urine sugar tests, check with your doctor.
  • Check with your doctor right away if you are having trouble breathing or if you experience a respiratory infection (such as pneumonia). This could result in a serious respiratory condition.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

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 fast heartbeat.
  • Dark-colored urine or pale stools.
  • Fever that does not go away or gets higher.
  • Fever, chills, cough, runny or stuffy nose, sore throat, or body aches.
  • Increased hunger or thirst.
  • Nausea, vomiting, loss of appetite, or pain in your upper stomach.
  • Numbness, tingling, or burning pain in your hands, arms, legs, or feet.
  • Severe stomach pain or bloody diarrhea.
  • Swelling in your hands, ankles, or feet.
  • Trouble with breathing.
  • Unusual bleeding, bruising, or weakness.
  • Unusual thoughts or behavior, depression, mood changes, or thoughts of hurting yourself or others.
  • Yellowing of your skin or the whites of your eyes.

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

  • Blurred vision.
  • Hair loss or thinning of the hair.
  • Headache, irritability, mild depression, nervousness, dizziness, or trouble with sleeping.
  • Mild "flu" symptoms, such as muscle aches and pains, low fever, or tiredness.
  • Mild nausea, vomiting, constipation, diarrhea, loss of appetite, or stomach pain or upset.
  • Pain in your back, joints, or muscles.
  • Pain, swelling, or redness where the shot was given.
  • Rash or itching skin.
  • Warmth or redness in your face, neck, arms, or upper chest.
  • Weight changes.

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: 11/4/2014
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