Interferon Alfa

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Interferon Alfa


Generic NameBrand Name
peginterferon alfa-2aPegasys
interferon alfa-2bIntron A

Interferon is usually given as a shot under the skin.

How It Works

Interferon is a man-made copy of a protein that is produced by the body in response to infection. It helps the immune system fight disease and may slow or stop the growth of cancer cells. It can make cancer cells too weak to protect themselves from the immune system.

Why It Is Used

Interferon may be used to treat some leukemias and other diseases, such as melanoma that has spread to the lymph nodes and chronic hepatitis C.

How Well It Works

Research shows that interferon is better than busulfan or hydroxyurea in treating CML. But interferon also causes more side effects.1

The use of interferon may increase the survival rate of some people with melanoma.2

Side Effects

Side effects of treatment with interferon are common and may include:

  • Flu-like symptoms, such as headaches, muscle aches, fever, chills, and fatigue. You may be able to feel better if you take the drug at bedtime along with a pain reliever such as acetaminophen (for example, Tylenol).
  • Loss of appetite and weight loss.
  • Nausea and vomiting.
  • Irritability.
  • Insomnia.
  • Depression.
  • Low blood counts, which may increase your risk of infection or bleeding.

Rare side effects include:

  • Confusion.
  • Excessive amounts of protein in the urine.
  • Hair loss.
  • Suicidal behaviour.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Interferon should be used only under the supervision of a medical oncologist or hematologist. When interferon is used for chronic viral hepatitis, a hepatologist or gastroenterologist is most likely to supervise treatment.

Interferon may be combined with cytarabine or imatinib to treat CML. It can also be used with other drugs to treat melanoma or kidney cancer.

Clinical trials are studying the use of interferon for melanoma that has spread or come back.

Interferon can cause birth defects. Taking this medicine is not recommended if you wish to become pregnant or to father a child while you are taking it. But for young women with chronic myelogenous leukemia (CML) who are pregnant, there may be less risk in taking this medicine compared to other medicines, such as tyrosine kinase inhibitors (TKIs).

Do not use alcohol or illegal drugs while you are being treated with interferon.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.



  1. Reichard KK, et al. (2009). Chronic myeloid leukemia. In JP Greer et al., eds., Wintrobe's Clinical Hematology, 12th ed., vol. 2, pp. 2006–2030. Philadelphia: Lippincott Williams and Wilkins.
  2. Kirkwood JM, et al. (2004). A pooled analysis of Eastern Cooperative Oncology Group and intergroup trials of adjuvant high-dose interferon for melanoma. Clinical Cancer Research, 10(5): 1670–1677.


By Healthwise Staff
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Primary Medical Reviewer Anne C. Poinier, MD - Internal Medicine
Specialist Medical Reviewer Brian Leber, MDCM, FRCPC - Hematology
Last Revised February 9, 2011

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