Interferon (cont.)

Tissue damage at the site of injection occurs with all of the interferons but more commonly with interferon beta-1b and pegylated interferon alfa-2b.

Depression and suicide have been reported among patients receiving interferons; however, it is unclear whether depression and suicidal thoughts are caused by the diseases being treated or the interferons themselves. Therefore, all patients receiving treatment with an interferon should be observed for the development of depression and suicidal thoughts.

Other side effects that may occur with all interferons and which may be caused by higher doses are:

Anorexia, congestion, increased heart rate, confusion, low white blood cell count, low platelet count (thrombocytopenia), low red blood cell count, an increase in liver enzymes, an increase in triglycerides, skin rashes, mild hair loss or hair thinning, swelling (edema), cough, or difficulty breathing have been reported.

Allergic and anaphylactic reactions may also occur.

Some interferons are associated with liver failure and periodic liver function tests are recommended during therapy.

With which drugs do interferons interact?

Interferon alfa-2a, interferon alfa-2b and interferon beta-1b may increase blood levels of zidovudine (AZT, Retrovir). While this reaction may improve zidovudine's effectiveness, it also may increase the risk of blood and liver toxicity. Therefore, the dose of zidovudine may need to be reduced by as much as 75%.

Interferon alfa-2a and interferon alfa-2b may increase the time it takes for theophylline (for example, THEO-DUR) to be eliminated from the body, and the dose of theophylline may need to be reduced.

What are the available interferons?

  • Roferon-A (interferon alfa-2a)

  • Intron-A (interferon alfa-2b)

  • Alferon-N (interferon alfa-n3)

  • PegIntron (peginterferon alfa-2b)

  • Avonex (interferon beta-1a)

  • Rebif (interferon beta-1a)

  • Betaseron (interferon beta-1b)

  • Extavia (interferon beta-1b)

  • Infergen (interferon alfacon-1)

  • Actimmune (interferon gamma-1b)

  • Pegasys (peginterferon alfa-2a)

  • Peginterferon (peginterferon alfa-2a and Ribavirin)

  • PegIntron/Rebetol combo pack (peginterferon alfa-2b and Ribavirin)

Reference: FDA Prescribing Information


Last Editorial Review: 3/30/2010



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