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Hepatitis B
Nucleoside Analogs
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Agents: entecavir, adefovir, telbivudine
Analogs of viral nucleosides are useful not just for
the treatment of HIV infection, but for HBV infection
as well. Because HBV is a DNA virus, they
can compete for viral enzymes with native viral
nucleosides just as they do for reverse transcriptase
in HIV. Several of them are active in both HIV
and HBV infection, an obvious bonus for patients
who are infected with both viruses. All are easy-totake
drugs that have changed the management of
HBV to offer an interferon-free regimen that is prolonged,
but well-tolerated. Several HIV nucleoside/
tide reverse transcriptase inhibitors are also used
to treat HBV, and tenofovir is a drug-of-choice in
both disease states.
Mechanism of Action
Nucleoside analogs inhibit the action of viral DNA
polymerase by taking the place of nucleotides in
the elongating strand of viral DNA, leading to
early termination of the viral DNA strain.
Spectrum
All of these drugs are active against HBV and
HIV, though they are not primarily used for HIV
infection.