Drug reference

Famciclovir

Antiviral

Also known as FCV, FAMVIR

AntiviralATC J05AB09

CDSCO approvedSchedule HATC J05AB09

EXCRETION

—

not curated

INTERACTIONS

—

none in our sources

PREGNANCY

Manufacturers advise avoid unless potential beneﬁt outweighs risk.

FDA category + note

Mechanism

Famciclovir is a prodrug that is rapidly converted to its active metabolite, penciclovir. Penciclovir is an antiherpesvirus agent that interferes with herpesvirus replication. Similar to other agents in its class, it likely inhibits viral DNA synthesis by targeting viral enzymes involved in genome replication.

Indications

Herpes zosterGenital herpesHSV infectionsVZV infectionsfirst-episode genital herpesrecurrent genital HSVsuppression of recurrent genital HSVchronic HBV hepatitis (reduces HBV DNA and transaminase levels, but less effective than lamivudine)herpes simplex keratitis (off-label)herpes zoster ophthalmicusgenital herpes simplex (first episode)genital herpes simplex (recurrent episode)genital herpes simplex (suppressive treatment)orolabial herpesherpes zoster (reduces duration of post herpetic neuralgia)chronic hepatitis B (less active alternative to lamivudine, but not for resistant cases)ZosterSuppression of genital herpesRecurrent mucocutaneous herpes in patients with HIV infection

Dosing

Adult: For Herpes zoster infection, treatment: 500 mg 3 times a day for 10 days, continue for 2 days after crusting of lesions; alternatively, 250 mg 3 times a day for 5 days.
Renal adjustment: Reduce dose; consult product literature.
Hepatic adjustment: Efficacy may be decreased in severe impairment (risk of impaired conversion to active metabolite, no information available).