Drug Database: Famciclovir

What is famciclovir?

Famciclovir is an antiviral prescription medicine approved by the U.S. Food and Drug Administration (FDA) for the treatment of herpes simplex virus (HSV) and varicella zoster virus (VZV) infections.

In adults with normal immune systems, famciclovir is FDA-approved:

• To treat recurrent outbreaks of cold sores (also known as herpes labialis or orolabial herpes) caused by HSV
• To treat recurrent outbreaks of genital herpes caused by HSV and to prevent outbreaks from reoccurring (called chronic suppressive therapy)
• To treat shingles (also known as herpes zoster) caused by VZV

In adults with HIV, famciclovir is FDA-approved:

• To treat recurrent outbreaks of orolabial or genital herpes caused by HSV

HSV and VZV infections can be opportunistic infections (OIs) of HIV. An OI is an infection that occurs more frequently or is more severe in people with weakened immune systems—such as people with HIV—than in people with healthy immune systems. To learn more about OIs, read the HIVinfo What is an Opportunistic Infection? fact sheet.

How is famciclovir used in people with HIV?

The Guidelines for the Prevention and Treatment of Opportunistic Infections in Adults and Adolescents with HIV include recommendations on the uses of famciclovir in people with HIV.

The recommended uses may not always be consistent with FDA-approved uses of famciclovir. See the guidelines for complete information on recommended uses of famciclovir in adults and adolescents with HIV. Famciclovir may have other recommended uses not listed above. 

What should I tell my health care provider before taking famciclovir?

Before taking famciclovir, tell your health care provider:

• If you are allergic to famciclovir or any other medicines.
• About any medical conditions you have or have had, for example, kidney or liver problems.
• About anything that could affect your ability to take medicines, such as difficulty swallowing or remembering to take pills.
• If you are pregnant or plan to become pregnant. Talk to your health care provider about the risks and benefits of using famciclovir during pregnancy. The Guidelines for the Prevention and Treatment of Opportunistic Infections in Adults and Adolescents with HIV and the Guidelines for the Prevention and Treatment of Opportunistic Infections in HIV-Exposed and HIV-Infected Children may include other recommendations on the use of famciclovir during pregnancy. Please refer to these guidelines for additional information. 
• If you are breastfeeding or plan to breastfeed. For women with HIV in the United States, the Guideline does not recommend breastfeeding. Before your baby is born, or if you are already breastfeeding, talk to your health care provider to discuss alternative options for feeding your baby.
• About other prescription and nonprescription medicines, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Famciclovir may affect the way other medicines or products work, and other medicines or products may affect how famciclovir works. Ask your health care provider if there are interactions between famciclovir and the other medicines you take.

Ask your health care provider about possible side effects from famciclovir. Your health care provider will tell you what to do if you have side effects.

How should I take famciclovir?

Take famciclovir according to your health care provider’s instructions. Your health care provider will tell you how much famciclovir to take and when to take it. Before you start famciclovir and each time you get a refill, read any printed information that comes with your medicine.

How should famciclovir be stored?

• Store famciclovir at room temperature, 68°F to 77°F (20°C to 25°C).
• Do not use famciclovir if the original seal over the container opening is broken or missing.
• Throw away famciclovir that is no longer needed or expired (out of date). Follow FDA guidelines on how to safely dispose of unused medicine.
• Keep famciclovir and all medicines out of reach of children.

Where can I find more information about famciclovir?

More information about famciclovir is available:

• Recommendations on the use of famciclovir in people with HIV, from the Guidelines for the Prevention and Treatment of Opportunistic Infections in Adults and Adolescents with HIV and the Guidelines for the Prevention and Treatment of Opportunistic Infections in HIV-Exposed and HIV-Infected Children, prepared by the Centers for Disease Control and Prevention, the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America, and the Pediatric Infectious Diseases Society.
• Famciclovir-related research studies, from ClinicalTrials.gov