Peginterferon for hepatitis C

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Peginterferon for hepatitis C


Generic NameBrand Name
peginterferon alfa-2aPegasys
peginterferon alfa-2bUnitron Peg and Intron A

How It Works

Peginterferons are a complex family of proteins that are produced by the body and that help you fight disease. They also can stop viruses from multiplying and damaging the body.

Peginterferon is given as a shot once a week to treat long-term (chronic) hepatitis C.

Peginterferons most often are combined with another medicine called ribavirin for the best results. Sometimes they are given without ribavirin. A person may not be given ribavirin if he or she has anemia, a heart problem, or a kidney problem.

Why It Is Used

Peginterferons may be used to treat chronic hepatitis C if you have:

  • Liver enzyme levels that remain elevated for more than 6 months. This indicates that you probably have long-term, chronic liver inflammation caused by the hepatitis C virus.
  • Detectable levels of hepatitis C virus in your blood.
  • Evidence of significant liver damage. This is detected with a liver biopsy.

How Well It Works

For many years, combination therapy with interferon and ribavirin was the standard treatment. Now, the combination of peginterferon and ribavirin is considered the best treatment for hepatitis C.

How well treatment works is measured by whether you still have the virus in your blood 6 months after treatment. If you are treated with interferons alone (interferon monotherapy), treatment generally works 10% to 20% of the time.1 When interferons or peginterferons are combined with ribavirin, treatment works anywhere from 40% to 80% of the time.1 Treatment is more likely to work if:

  • You have a low level of the hepatitis C virus in your blood when treatment starts.
  • You have genotype 2 or 3.
  • You have a small amount of liver damage when treatment starts.
  • You do not have HIV.
  • You do not abuse alcohol.

Side Effects

Side effects from interferon, peginterferon, and ribavirin are common. If your side effects are severe, you may need to stop treatment. Some side effects may decrease as treatment continues.

Common side effects of combination antiviral therapy include:

If you develop anemia as a result of taking ribavirin, your doctor may prescribe a medicine called erythropoietin to help your body create more red blood cells.

Most side effects go away when you stop taking the medicines.

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

What To Think About

Treatment for chronic hepatitis C lowers the chance of liver cancer.2

You will need routine follow-up visits with a liver specialist during treatment. The specialist will order blood tests to check your liver enzyme levels and to see whether the virus is still multiplying.

A person with normal or slightly elevated liver enzyme levels but whose liver biopsy shows little or no liver damage may choose not to have antiviral treatment. Instead, a doctor can monitor these conditions with periodic liver function tests and a liver biopsy every 3 to 5 years.

Even if the initial treatment does not get rid of the virus, your doctor may advise you to continue antiviral treatment, because it may reduce liver inflammation. For some people with significant liver damage, antiviral therapy may slow the progression of liver damage or make liver cancer less likely. If you already have cirrhosis, some studies show that antiviral therapy can help you live longer.3

If it is possible that you are pregnant, you will need a pregnancy test. Women and men who are taking ribavirin need to avoid getting pregnant or fathering a child, because this medicine can damage a developing fetus. Women who could become pregnant and their partners must use two reliable forms of birth control during treatment and for 6 months after treatment, to avoid pregnancy.

Only a few clinical trials have tested antiviral medicines in children. Results suggest that they work about as well in children as in adults.

If you are obese or have diabetes, you may need to delay treatment until you get your weight or blood sugar under control.

If you have tried interferon in the past and did not get good results, talk to a doctor who is a liver specialist (hepatologist). The hepatologist will be able to tell you about newer combinations of peginterferon with ribavirin or new, experimental treatments.

The long-term health effects of combination antiviral therapy are not known at this time.

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  1. Hoofnagle JH (2008). Chronic hepatitis C. In L Goldman, D Ausiello, eds., Cecil Medicine, 23rd ed., pp. 1113–1116. Philadelphia: Saunders Elsevier.
  2. Shiratori Y, et al. (2005). Antiviral therapy for cirrhotic hepatitis C: Association with reduced hepatocellular carcinoma development and improved survival. Annals of Internal Medicine, 142(2): 105–114.
  3. Dienstag JL (2005). Chronic viral hepatitis. In GL Mandell et al., eds., Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 6th ed., vol. 1, pp. 1441–1464. Philadelphia: Elsevier/Churchill Livingstone.


By Healthwise Staff
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer W. Thomas London, MD - Hepatology
Specialist Medical Reviewer Donald Sproule, MD, CM, CCFP, FCFP - Family Medicine
Last Revised October 9, 2009

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