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Advances in molecular virology,
with the identification of viral-specific enzymes, led to the development
of a number of antiviral agents. Effective antivirals currently
are available for the management of infections caused by herpes
simplex virus (HSV), varicella-zoster virus (VZV), cytomegalovirus
(CMV), hepatitis B and C viruses, influenza A and B viruses, and
human immunodeficiency virus (HIV). To maximize therapeutic efficacy,
treatment should be initiated as early in the course of infection
as possible. Under some circumstances (eg, recurrent herpes simplex
virus infections and exposure to influenza virus), antivirals may
be effective in the prevention of infection. Development of resistance to
antivirals is emerging as a problem, especially in the immunocompromised
host population and more recently with influenza viruses circulating in
the general population.
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Subtle modifications of antiviral compounds have led to the development
of drugs with increased bioavailability after oral administration.
Many of these drugs are now used extensively in the outpatient setting
(Table 245-1). However, severe viral infections,
especially in immunocompromised hosts, require aggressive parenteral
therapy, often with high doses of antiviral drugs (Table
245-2).1-3
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