The reference site for Famciclovir

Famciclovir is a guanosine analogue antiviral drug used for the treatment of various herpesvirus infections, most commonly for herpes zoster (shingles).

WHAT IS Famciclovir?

Famciclovir is an antiviral drug. It works by slowing the growth and spread of the herpes virus so that the body can fight off the infection. Famciclovir shortens the length of time symptoms are present.

This medicine is also used to treat infections caused by herpes viruses including shingles, genital herpes, and cold sores (in people with HIV).

Famciclovir is marketed under the trade name Famvir® (Novartis).


Brand Name(s): Famvir
CAS nº: 104227-87-4


Product Info

The sections below will provide you with more specific information and guidelines related to famciclovir and its correct use. Please read them carefully.

FDA Information

Famciclovir was approved for use by the FDA in 1994. A prescription is required for this medicine.

Please visit the official site of the FDA for further information.

Why is this medication prescribed?

Famciclovir is used to treat infections caused by herpes viruses including shingles, genital herpes, and cold sores (in people with HIV).

It inhibits the replication of viral DNA that is necessary in order for viruses to reproduce themselves. Famciclovir is actually a “prodrug,” in that it is not active directly against viruses. Instead, famciclovir is converted to penciclovir in the body, and it is the penciclovir that is active against the viruses.

Additionally, this medicine is active against the same viruses as acyclovir but has a longer duration of action. Therefore, it can be taken fewer times each day.

Other uses for this medicine

This medication has not been approved for any alternative uses other than those mentioned in the product information section.

Dosage and using this medicine

Famciclovir comes as a tablet that is administered orally. It is usually taken every 8 hours (three times a day) for 7 days to treat shingles. To treat genital herpes it is usually taken twice a day for 5 days.

Always take famciclovir exactly as directed by your doctor. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.

Treatment with famciclovir should be started as soon as possible after the first appearance of symptoms (e.g. tingling, burning, blisters).

Take each dose with a full glass of water. Moreover, this medication can be taken with or without food. Taking famciclovir with food may decrease stomach upset.

Take all of the famciclovir that has been prescribed for you even if you begin to feel better. Your symptoms may start to improve before the infection is completely treated.

Lesions caused by herpes viruses should be kept as clean and dry as possible. Wearing loose clothing may help to prevent irritation of the lesions.

What special precautions should I follow?


Tell your doctor if you have kidney disease. You may need a dosage adjustment or special monitoring during treatment with famciclovir.

Do not take famciclovir if you are allergic to penciclovir (Denavir®) without first talking to your doctor.

Famciclovir is in the FDA pregnancy category B. This means that it is unlikely to harm an unborn baby. Do not take famciclovir without first talking to your doctor if you are pregnant.

Furthermore, it is not known whether famciclovir passes into breast milk. Do not take famciclovir without first talking to your doctor if you are breast-feeding a baby.

The safety and effectiveness of famciclovir have not been established for children younger than 18 years of age.

Herpes infections are contagious and you can infect other people, even during treatment. Avoid letting infected areas come into contact with other people, and it is strongly advised that you wash your hands frequently to prevent transmission.

Please note that famciclovir will not prevent the spread of genital herpes. Avoid sexual intercourse or use a latex condom to prevent spreading the virus to others.

What should I do if I forget a dose?

Take the missed dose as soon as you remember. However, if it is almost time for the next regularly scheduled dose, skip the missed dose and take the next one as directed.

Do not take a double dose of this medication unless otherwise directed by your doctor.

What side effects can this medication cause?

Possible side effects from famciclovir may include:


Tell your doctor if any of these symptoms are severe or do not go away:

nausea or vomiting
a headache
tingling in your hands or feet

If you experience any of the following symptoms, call your doctor immediately:

an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives)

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

What storage conditions are needed for this medicine?

Always keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

Remember to throw away any medication that is outdated or no longer needed and talk to your pharmacist about the proper disposal of your medication.

In case of an emergency/overdose

If you suspect of an overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call the local emergency services on 911.

A famciclovir overdose has no known symptoms.

Product Images


Below you will find images and specific information on the principal types of famciclovir that exist, including their respective brand name(s), strength, inscription codes, manufacturers and/or distributors.

The information below includes general information and guidelines for patients taking this medication and should never be used to substitute professional medical advice that can be provided by a qualified physician or family doctor.

Strength(s): 250 MG
Imprint: FAMVIR | 250
Manufacturer: NOVARTIS

Strength(s): 500 MG
Imprint: FAMVIR | 500
Manufacturer: NOVARTIS

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