Famciclovir

Preview FDA label, AvKARE, oral, effective 2026-07-21. Full label on DailyMed

Quoted from the FDA label. Product labels differ by manufacturer and change over time; confirm against the label for the product you are using. Not yet reviewed by a ClinDose pharmacist.

Dosing in kidney impairment

Dosing Recommendation in Patients with Renal Impairment Dosage recommendations for adult patients with renal impairment are provided in Table 1 [see Use in Specific Populations, Clinical Pharmacology]. Table 1: Dosage Recommendations for Adult Patients with Renal Impairment [See table below.] Suppression of Recurrent Genital Herpes 250 mg every 12 hours ≥40 250 every 12 hours 20-39 125 every 12 hours <20 125 every 24 hours HD* 125 following each dialysis Recurrent Orolabial or Genital Herpes in HIV-Infected Patients 500 mg every 12 hours ≥40 500 every 12 hours 20-39 500 every 24 hours <20 250 every 24 hours HD* 250 following each dialysis *Hemodialysis

Indication and Normal Dosage Regimen Creatinine Clearance (mL/min) Adjusted Dosage Regimen Dose (mg) Dosing Interval
Single-Day Dosing Regimens Recurrent Genital Herpes 1000 mg every 12 hours for1 day ≥60 1000 every 12 hours for 1 day
40-59 500 every 12 hours for 1 day
20-39 500 single dose
<20 250 single dose
HD* 250 single dose following dialysis
Recurrent Herpes Labialis 1500 mg single dose ≥60 1500 single dose
40-59 750 single dose
20-39 500 single dose
<20 250 single dose
HD* 250 single dose following dialysis
Multiple-Day Dosing Regimens
Herpes Zoster 500 mg every 8 hours ≥60 500 every 8 hours
40-59 500 every 12 hours
20-39 500 every 24 hours
<20 250 every 24 hours
HD* 250 following each dialysis
Suppression of Recurrent Genital Herpes 250 mg every 12 hours ≥40 250 every 12 hours
20-39 125 every 12 hours
<20 125 every 24 hours
HD* 125 following each dialysis
Recurrent Orolabial or Genital Herpes in HIV-Infected Patients 500 mg every 12 hours ≥40 500 every 12 hours
20-39 500 every 24 hours
<20 250 every 24 hours
HD* 250 following each dialysis

Dosing in liver impairment

Patients with Hepatic Impairment Mild or moderate hepatic impairment (chronic hepatitis [n=6], chronic ethanol abuse [n=8], or primary biliary cirrhosis [n=1]) had no effect on the extent of availability (AUC) of penciclovir following a single dose of 500 mg famciclovir. However, there was a 44% decrease in penciclovir mean maximum plasma concentration (C max ) and the time to maximum plasma concentration (t max ) was increased by 0.75 hours in patients with hepatic impairment compared to normal volunteers.

No dosage adjustment is recommended for patients with mild or moderate hepatic impairment. The pharmacokinetics of penciclovir has not been evaluated in patients with severe hepatic impairment. Conversion of famciclovir to the active metabolite penciclovir may be impaired in these patients resulting in a lower penciclovir plasma concentrations, and thus possibly a decrease of efficacy of famciclovir [see Clinical Pharmacology].

Calculators for famciclovir