How It Works
Interferon is a man-made copy of a protein that your body makes in response to infection. It helps the immune system fight disease and may slow or stop the growth of the hepatitis B virus in your body.
Interferon is given as a shot 3 times a week. A slow release form of interferon, pegylated interferon (also known as peginterferon), is given as a shot once a week. Peginterferon is used more often than interferon to treat hepatitis B. Treatment with interferons can last 4 months to 1 year.
Why It Is Used
Interferons are used to treat long-term (chronic) HBV infection in adults and children who are at risk for liver disease. The American Association for the Study of Liver Disease has made recommendations on who should receive treatment for hepatitis B based on the presence of hepatitis B antigen in your blood, the level of hepatitis B virus DNA (HBV DNA) in your blood, and the level of the liver enzyme alanine aminotransferase (ALT).1
Treatment with interferons is not recommended if you are using illegal drugs or drinking too much alcohol. It is also not recommended if you have had an organ transplant or if you have advanced liver scarring (cirrhosis).
Interferons can cause or aggravate mental problems. Tell your doctor if you have a history of depression, suicidal thoughts, anxiety, drug or alcohol abuse, or mental illness.
How Well It Works
It is important to weigh the benefits of treatment against the risks. Treatment for HBV infection is considered successful if blood tests show that the virus is no longer multiplying in the body, if liver enzyme levels return to normal, and if liver damage (such as inflammation and scarring) improves.
The success of interferon treatment for hepatitis B depends on how treatment success is defined. Relapse-when the virus starts to multiply again-is common after treatment is stopped. Interferons stop the growth of the virus over the long term in about 35% of people who use them.1 Recent studies suggest that peginterferon works a little better than interferon.2, 3
Interferons work best for people who have high levels of liver enzymes and in whom the virus is multiplying. They are also more likely to work in people who have a strong immune system, who have had hepatitis for a short amount of time, and who became infected after childhood.4
All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.
Here are some important things to think about:
- Usually the benefits of the medicine are more important than any minor side effects.
- Side effects may go away after you take the medicine for a while.
- If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.
Call911or other emergency services right away if you have:
Call your doctor if you have:
Common side effects of these medicines include:
See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)
What To Think About
- Interferons have several advantages over other medicines used to treat chronic hepatitis B:
- Drug resistance has not developed with interferon use. Resistance has developed with the use of other medicines to treat chronic HBV. Drug resistance occurs when viruses change over time and can no longer be killed by medicines that killed them in the past.
- Treatment is done for a shorter length of time than treatment with other HBV medicines. For example, treatment with an interferon may last for 16 to 48 weeks. And treatment with a nucleoside reverse transcriptase inhibitor (NRTI) usually lasts for years.
- Interferons have some potential disadvantages compared to other medicines used to treat chronic hepatitis B:
- Interferons are expensive, but you usually take them for just 4 to 12 months. Other medicines may need to be taken for longer periods of time.
- They must be given as injections (shots).
- Interferons are more likely to cause side effects than are other medicines used to treat hepatitis B.
- Experts do not know if interferons are safe for pregnant women. Interferons are not considered safe for women who are breast-feeding.
Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.
There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.
Advice for women
If you are pregnant, breast-feeding, or planning to get pregnant, do not use any medicines unless your doctor tells you to. Some medicines can harm your baby. This includes prescription and over-the-counter medicines, vitamins, herbs, and supplements. And make sure that all your doctors know that you are pregnant, breast-feeding, or planning to get pregnant.
Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.
Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.
Lok SFL, McMahon BJ (2009). Chronic Hepatitis B: Update 2009. Available online: http://www.aasld.org/practiceguidelines/Documents/Bookmarked%20Practice%20Guidelines/Chronic_Hep_B_Update_2009%208_24_2009.pdf.
Janssen, H (2005). Pegylated interferon alfa-2b alone or in combination with lamivudine for HBeAg-positive chronic hepatitis B: A randomised trial. Lancet, 365(9454): 123-129.
Lau GKK, et al. (2005). Peginterferon alfa-2a, lamivudine, and the combination for HBeAG-positive chronic hepatitis B. New England Journal of Medicine, 352(26): 2682-2695.
Dienstag JL (2010). Chronic viral hepatitis. In GL Mandell et al., eds., Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 7th ed., vol. 1, pp. 1593-1670. Philadelphia: Churchill Livingstone Elsevier.
Primary Medical ReviewerKathleen Romito, MD - Family Medicine
Specialist Medical ReviewerW. Thomas London, MD - Hepatology
Current as ofNovember 14, 2014