Pharm

Interferon Alfa-2B

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Interferon Alfa-2B, Intron A, Interferon alfa, Interferon-alfa

  • Contraindications
  • Mechanism
  1. Interferon is an endogenous Cytokine (integral to inflammatory and immune responses)
    1. Released from Lymphocytes, Dendritic Cells, Macrophages, fibroblasts, Natural Killer Cells and T Cells
  2. Interferon is subdivided into three main types (alpha, beta, gamma)
    1. Alpha and beta Interferon both have Antiviral activity
    2. Synthesized alpha Interferon has primarily been used for Viral Hepatitis B and C infection, as well as cancer
    3. Synthesized beta Interferon has primarily been used to treat Multiple Sclerosis
  3. Alpha Interferon binds cell-surface receptors on viruses and cancer cells
    1. Modulates transcription and translation of genes, inhibiting replication in virus infected cells
    2. Interferon Alpha-2B is a non-glycosylated recombinant Interferon that has Antiviral and antineoplastic activity
  1. Peginterferon Alpha-2A is preferred instead
  2. Adult
    1. Dose 5 MU SQ or IM daily OR for 16 weeks
    2. Dose 10 MU SQ or IM three times weekly for 16 weeks
  3. Child (age >=1 year)
    1. Start: 3 MU/m2 SQ three times per week for the first week, then
    2. Next: 6 MU/m2 (up to 10 MU) SQ three times weekly
  • Efficacy
  1. Synergistic effect when combined with Ribavirin
  2. Sustained response in 10-30% of cases of Hepatitis B
  3. Poor response when coinfected with HIV
  4. Improved response rates with
    1. Low levels of Viremia
    2. Absence of Cirrhosis
    3. Early response to Interferon
    4. Low total body iron
  • Adverse Effects
  1. Transient Flu-like symptoms (>50%)
    1. Fever and chills
    2. Headache
    3. Myalgia
    4. Nausea
    5. Diarrhea
  2. Early: Decreased cell lines (higher risk in HIV Infection)
    1. Decreased Granulocytes
    2. Thrombocytopenia
  3. Later
    1. Fatigue
    2. Major Depression
    3. Suicidality
    4. Alopecia
    5. Rash
    6. Retinal Hemorrhages
    7. Autoimmune Thyroid disease
    8. Hepatotoxicity
    9. Hypertriglyceridemia
  • Safety
  1. Unknown safety in pregnancy
  2. Unknown safety in Lactation
  • Monitoring
  1. Initial flu-like symptoms
    1. Acetaminophen (Tylenol)
  2. Periodic labs
    1. Complete Blood Count (CBC)
      1. Decrease dosage or discontinue Interferon if Hemolytic Anemia
    2. Thyroid Stimulating Hormone (TSH)
    3. Liver Function Tests
      1. Discontinue Interferon if LFTs have not normalized by week 12
    4. Serum Triglycerides