Drug reference
penciclovir
Acyclic guanine nucleoside analogue · Antiviral (Antiherpesvirus)
Acyclic guanine nucleoside analogueAntiviral (Antiherpesvirus)
CDSCO approved
EXCRETION
—
not curated
INTERACTIONS
—
none in our sources
PREGNANCY
—
not curated
Mechanism
Penciclovir is an acyclic guanine nucleoside analogue that inhibits viral DNA synthesis. In HSV- or VZV-infected cells, it is phosphorylated initially by viral TK to penciclovir triphosphate, a competitive inhibitor of viral DNA polymerase. It inhibits DNA elongation but is not an obligate chain terminator.
Indications
HSV infectionsVZV infectionsmucocutaneous HSV infections in immunocompromised hosts (intravenous, not available in U.S.)recurrent orolabial HSV (topical)
Pharmacokinetics
Half-life
~2 h (plasma elimination); 7 to 20 h (intracellular penciclovir triphosphate)
Bioavailability
<5% (oral)
Excretion
More than 90% excreted unchanged in the urine; efficiently removed by hemodialysis
Side effects
Common
local reactions (topical, ~1%)
Serious
- mutagenic (at high concentrations)
Related guidelines
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Sources: Goodman & Gilman 14e·Verified: 2026-05-10 · House clinical team