Uses

Famciclovir is an oral antiviral prodrug indicated for treatment of herpes zoster (shingles), recurrent genital herpes (treatment and suppression), and recurrent herpes labialis (cold sores) in immunocompetent adults. Also indicated for treatment of recurrent orolabial or genital herpes in HIV-infected adults.

Do not use if

Contraindicated in patients with known hypersensitivity to famciclovir, penciclovir, or any component of the formulation.

Side effects

The most common adverse effects (>10%) are headache and nausea. Other reported effects include diarrhea, fatigue, and abdominal pain. Acute renal failure has been reported rarely, particularly with inappropriate dosing in renal impairment.

Warnings

Reduce dose in patients with renal impairment to avoid accumulation and risk of acute renal failure. Use with caution in elderly patients who may have reduced renal function. Efficacy not established for initial genital herpes episodes or in immunocompromised patients beyond HIV infection.

How it works

Famciclovir is a prodrug that is rapidly converted to penciclovir after oral absorption. Penciclovir is a deoxynucleoside analog that inhibits viral DNA polymerase in herpes virus-infected cells, thereby blocking viral replication.

Storage

Store at room temperature 20°C to 25°C (68°F to 77°F). Protect from moisture.