Trade Names:Famvir- Tablets 125 mg- Tablets 250 mg- Tablets 500 mgApo-Famciclovir (Canada)PMS-Famciclovir (Canada)Sandoz Famciclovir (Canada)
Converts to penciclovir, which inhibits viral DNA replication by interfering with viral DNA polymerase.
Bioavailability is about 77%. T max is 0.9 h. AUC 0-∞ is 2.24 to 17.9 mcg•h/mL depending on dose. C max is 0.8 to 6.6 mcg/mL depending on dose.
Vd is about 1.08 L/kg; less than 20% bound to plasma proteins.
Route is the liver; deacetylated and oxidized to form inactive penciclovir metabolites.
Plasma Cl is about 36.6 L/h; about 75% is renally cleared. The t ½ is about 2 to 3 h.
With CrCl 40 to 59 mL/min, Cl is about 13 L/h and t ½ is about 3.4 h. With CrCl 20 to 39 mL/min, Cl is about 4.2 L/h and t ½ is about 6.2 h. With CrCl less than 20 mL/min, Cl is about 1.6 L/h and t ½ is about 13.4 h.Hepatic Function Impairment
Penciclovir C max decreased 44% and T max increased 0.75 h.
Treatment of acute herpes zoster (shingles); treatment or suppression of recurrent genital herpes in immunocompetent patients; treatment of recurrent mucocutaneous herpes simplex infections in HIV-infected patients; treatment of recurrent herpes labialis (cold sores) in immunocompetent patients.
Management of initial episodes of herpes genitalis.
Hypersensitivity to famciclovir, other components of the formulation, or penciclovir cream.
PO 1,000 mg twice daily for 1 day. Initiate therapy at first sign or symptom. Efficacy not established when treatment is started more than 6 h after onset of symptoms or lesions.Recurrent Herpes Labialis
PO 1,500 mg as a single dose. Initiate therapy at earliest sign or symptom of a cold sore.Suppression of Recurrent Genital Herpes
PO 250 mg twice daily for up to 1 yr.Renal Function Impairment Recurrent Genital Herpes
PO For CrCl at least 60 mL/min, 1,000 mg every 12 h for 1 day; for CrCl 40 to 59 mL/min, 500 mg every 12 h for 1 day; for CrCl 20 to 39 mL/min, 500 mg single dose; for CrCl less than 20 mL/min, 250 mg single dose; for hemodialysis, 250 mg single dose following dialysis.Recurrent Herpes Labialis
PO For CrCl 60 mL/min, 1,500 mg single dose; for CrCl 40 to 59 mL/min, 750 mg single dose; for CrCl 20 to 39 mL/min, 500 mg single dose; for CrCl less than 20 mL/min, 250 single dose; for hemodialysis, 250 mg single dose following dialysis.Suppression of Recurrent Genital Herpes
PO For CrCl 40 mL/min, 250 mg every 12 h; for CrCl 20 to 39 mL/min, 125 mg every 12 h; for CrCl less than 20 mL/min, 125 mg every 24 h; for hemodialysis, 125 mg following each dialysis.Herpes ZosterAdults
PO 500 mg every 8 h for 7 days. Initiate treatment immediately after diagnosis but no later than 72 h after onset of rash.Renal Function Impairment
PO For CrCl 60 mL/min or more, 500 mg every 8 h; for CrCl 40 to 59 mL/min, 500 mg every 12 h; for CrCl 20 to 39 mL/min, 500 mg every 24 h; for CrCl less than 20 mL/min, 250 mg every 24 h.HIV-Infected PatientsAdults Recurrent Orolabial or Genital Herpes
PO 500 mg twice daily for 7 days.Renal Function Impairment
PO for CrCl 40 mL/min, 500 mg every 12 h; for CrCl 20 to 39 mL/min, 500 mg every 24 h; for CrCl less than 20 mL/min, 250 mg every 24 h; for hemodialysis, 250 mg following each dialysis.
Store tablets at 59° to 86°F.
Famciclovir may increase digoxin serum concentration.Probenecid or other drugs significantly eliminated by active renal tubular secretion
May increase famciclovir (penciclovir) serum concentrations.
None well documented.
Headache (39%); fatigue (5%); migraine, paresthesia (3%); confusion, confusional state, delirium, disorientation, dizziness, hallucinations, somnolence (postmarketing).
Pruritus (4%); rash (3%); serious skin reactions (including erythema multiforme), urticaria (postmarketing).
Nausea (13%); diarrhea (9%); abdominal pain (8%); flatulence, vomiting (5%).
Anemia, leukopenia, neutropenia, thrombocytopenia (postmarketing).
Elevated amylase, ALT, AST, lipase, serum creatine, and total bilirubin (postmarketing).
For recurrent genital herpes, assess history of frequency of recurrence. Monitor for efficacy of treatment.
Category B .
Safety and efficacy not established.
Dosage adjustment is recommended when CrCl is 60 mL/min or less.
Sexual intercourse must be avoided when lesions are present. Use of famciclovir does not prevent transmission.
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