Interferons

The interferons include drugs such as peginterferon alfa-2a (Pegasys), peginterferon alfa-2b (Pegintron), recombinant interferon alfa-2a (Roferon), and recombinant interferon alfa-2b (Intron A).

• How do interferons work? Interferons are virus-fighting proteins the body makes naturally in response to viral infection. Interferons also have other actions in the body and have been used to treat a variety of diseases (for example, leukemias, other types of cancers, and multiple sclerosis).
  
  
• Who should not use these medications? Individuals with autoimmune hepatitis, decompensated liver disease, or allergy to interferons should not use these medications. Peginterferon cannot be used in newborns.
  
  
• Use: Peginterferon is given as an injection under the skin once per week. Recombinant interferon alfa-2a or alfa-2b is injected 3 times per week.
  
  
• Drug or food interactions: Peginterferon may increase theophylline levels in the blood.
  
  
• Side effects: Common side effects resemble flu symptoms and include fatigue, low blood cell counts (anemia), muscle aches, nausea and vomiting, mild fever, headache, and/or weight loss. Up to 20% of individuals experience depression. Interferon should be discontinued if a person’s depression becomes severe and he or she does not respond to antidepressant therapy or dose decreases. Periodic eye examinations are recommended.