antibioticsbooks

242 PART 5 Antiviral Drugs
Spectrum
Alpha interferons are used for the treatment of
infections caused by hepatitis B virus (HBV) and
hepatitis C virus (HCV).
Adverse Effects
adverse effects are very common with interferons,
leading to noncompliance, patient dropout, and
avoidance of their use. Flu like symptoms are most
common, including headache, fatigue, weakness,
fever, and myalgia. Depression is also common and
often requires pharmacologic treatment. Patients
with suicidal ideation should not be given interferons.
Anxiety can also occur.
Hematologic adverse effects are also common
with interferons, notably cytopenias including neutropenia,
anemia, and thrombocytopenia. In the
treatment of HCV infection, ribavirin is usually the
primary cause of anemia.
Interferons can worsen decompensated cirrhosis
and are generally not administered to these
patients.
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Important Facts
• Pegylated interferons have supplanted nonpegylated
forms for the treatment of viral
hepatitis. Pegylated forms are given onceweekly
compared to thrice-weekly for the nonpegylated
interferons, improving compliance
and convenience. Adverse effects are somewhat
attenuated also, and efficacy is either
similar or somewhat higher for the pegylated
forms.
• Dosing for these agents varies significantly
by agent and indication, so be cautious when