FAMVIR
General description

Famvir is the brand name for the drug famciclovir produced by Smithkline Beecham. Famciclovir is a prodrug of penciclovir. It is an acyclic guanine derivative that acts an an inhibitor of herpes simplex viruses 1 and 2 (HSV 1 and HSV 2) and varicella-zoster virus (VZV).

Mechanism

In the body, famciclovir is transformed to penciclovir, and acts in the same manner as penciclovir.

Indications

Famvir is indicated for use against acute herpes zoster. It is also indicated for treatment of recurrent genital herpes in immunocompromised patients and recurrent mucocutaneous herpes simplex infections of patients infected with HIV.

Usage/Dosage

Indication and normal dosage regimen	Creatine clearance (mL/min)	Adjusted Dosage Regimen	Dosing Interval
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
	hemodialysis	250	following each dialysis
Recurrent Genital Herpes 125 mg every 12 hours	>40	125	every 12 hours
	20-39	125	every 24 hours
	<20	125	every 24 hours
	hemodialysis	125	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
	hemodialysis	125	following each dialysis
Recurrent Orolabial and Genital Herpes Simplex Infection in HIV-Infected Patients 500 mg every 12 hours	>40	500	every 12 hours
	20-39	500	every 24 hours
	<20	205	every 24 hours
	hemodialysis	205	following each dialysis

Precautions

Patients should know that Famvir is not a cure for genital herpes. It is unknown whether Famvir can act to prevent transmission with others, so during treatment, patients should be careful of transmission. The drug has been found to be a carcinogen in rats, though no studies have been performed with humans yet. The efficacy of Famvir has not yet been established for treating initial episodes of genital herpes, ophtalmic zoster, disseminated zoster, or immunocompromised patients with herpes zoster.

Contraindications

Famvir is contraindicated for patients with known hypersensitivity to components of the drug, its product, or to Denavir.

Potential Adverse Effects

The most common side effect is headache. This drug appears to be relatively safe.