famciclovir

fam-SYE-kloe-veer

Therapeutic Classification: antivirals

REMS

Acute herpes zoster infections (shingles).
Treatment/suppression of recurrent herpes genitalis in immunocompetent patients.
Treatment of recurrent herpes labialis (cold sores) in immunocompetent patients.
Treatment of recurrent mucocutaneous herpes simplex virus (HSV) infection in patients with HIV.

Inhibits viral DNA synthesis in herpes-infected cells only.

Therapeutic effects:

Decreased duration of herpes zoster infection with decreased duration of viral shedding.
Decreased time to healing for cold sores.
Decreased lesion formation and improved healing in recurrent HSV infection.

Absorption: Following absorption, famciclovir is rapidly converted in the intestinal wall to penciclovir, the active compound.

Distribution: Unknown.

Metabolism/Excretion: Penciclovir is mostly excreted by the kidneys.

Half-Life: Penciclovir: 2.1–3 hr (↑ in renal impairment).

(penciclovir plasma concentrations)

ROUTE	ONSET	PEAK	DURATION
PO	rapid	0.9 hr	8–12 hr

Contraindicated in:

Hypersensitivity.

Use Cautiously in:

Renal impairment (↑ dose interval/↓ dose if CCr <40–60 mL/min);
OB: Use during pregnancy only if potential maternal benefit justifies potential fetal risk;
Lactation: Use during breastfeeding only if potential maternal benefit justifies potential risk to infant;
Pedi: Safety and effectiveness not established in children;
Geri: Consider age-related in renal function in older adults.

CV: palpitations

Derm: hypersensitivity vasculitis

GI: diarrhea, nausea, vomiting

GU: ↓fertility (males)

Neuro: headache, dizziness, fatigue, SEIZURES

Misc: ANAPHYLAXIS

Drug-drug:

Probenecid↑ levels of penciclovir.

Herpes Zoster

PO (Adults ): 500 mg every 8 hr for 7 days.

Renal Impairment

PO (Adults ): CCr 40–59 mL/min: 500 mg every 12 hr; CCr 20–39 mL/min: 500 mg every 24 hr; CCr <20 mL/min: 250 mg every 24 hr; Hemodialysis: 250 mg after each dialysis.

Recurrent Genital Herpes Simplex Infections

PO (Adults ): 1000 mg twice daily for one day.

Renal Impairment

PO (Adults ): CCr 40–59 mL/min: 500 mg twice daily for 1 day; CCr 20–39 mL/min: 500 mg as a single dose; CCr <20 mL/min: 250 mg as a single dose; Hemodialysis: 250 mg as a single dose after dialysis.

Suppression of Recurrent Herpes Simplex Infections

PO (Adults ): 250 mg every 12 hr for up to 1 yr.

Renal Impairment

PO (Adults ): CCr 20–39 mL/min: 125 mg every 12 hr for 5 days; CCr <20 mL/min: 125 mg every 24 hr for 5 days; Hemodialysis: 125 mg after each dialysis.

Recurrent Herpes Labialis Infections (Cold Sores)

PO (Adults ): 1500 mg as a single dose.

Renal Impairment

PO (Adults ): CCr 40–59 mL/min: 750 mg as a single dose; CCr 20–39 mL/min: 500 mg as a single dose; CCr <20 mL/min: 250 mg as a single dose; Hemodialysis: 250 mg as a single dose after dialysis.

Herpes Simplex in Patients with HIV

PO (Adults ): 500 mg every 12 hr for 7 days.

Renal Impairment

PO (Adults ): CCr 20–39 mL/min: 500 mg every 24 hr for 7 days; CCr <20 mL/min: 250 mg every 24 hr for 7 days; Hemodialysis: 250 mg after each dialysis.

(Generic available)

Tablets: 125 mg; 250 mg; 500 mg

Assess lesions prior to and daily during therapy.
Assess patient for postherpetic neuralgia periodically during and following therapy.

Famciclovir therapy should be started as soon as herpes zoster is diagnosed, at least within 72 hr, preferably within 48 hr.
PO: Famciclovir may be administered without regard to meals.

Instruct patient to take famciclovir as directed for the full course of therapy. Take missed doses as soon as remembered, if not just before next dose.
Inform patient that famciclovir does not prevent the spread of infection to others. Until all lesions have crusted, precautions should be taken around others who have not had chickenpox or varicella vaccine or people who are immunosuppressed.
Advise patient to use condoms during sexual contact and to avoid sexual contact while lesions are present.
May cause dizziness. Caution patient to avoid driving and other activities requiring alertness until response to medication is known.
Advise patient to notify health care professional immediately if seizures or signs and symptoms of anaphylaxis (rash, facial swelling, difficulty breathing) occur.
Instruct women with genital herpes to have yearly Papanicolaou (Pap) smears because of increased risk of cervical cancer.
Rep: Advise women of childbearing potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding. Encourage women who become pregnant while taking famciclovir to enroll in the pregnancy reporting system to monitor maternal-fetal outcomes. Report pregnancies and pregnancy outcomes to the Novartis Adverse Event reporting line at 1-888-NOW-NOVA (669-6682). May cause decreased fertility in male patients.

Decrease in time to full crusting, loss of vesicles, loss of ulcers, and loss of crusts in patients with acute herpes zoster (shingles).
Crusting over and healing of lesions in herpes labialis, genital herpes, and in recurrent mucocutaneous HSV infection in patients with HIV.
Prevention of recurrence of herpes genitalis.
Decreased time to healing for cold sores.

~~Famvir~~

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Route/Dosage ⬆ ⬇

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Assessment ⬆ ⬇

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US Brand Names ⬆