What is Famciclovir?

Commonly Used Brand Name(s)Famvir

Therapeutic ClassificationsAntiviral

OverviewTOP

Famciclovir is used to treat the symptoms of herpes zoster (also known as shingles), a herpes virus infection of the skin. It is used to treat and suppress herpes labialis (cold sores) and recurrent episodes of genital herpes infection. This medicine is also used to treat recurrent herpes virus infections of the mucous membranes (lips and mouth) and genitals in HIV-infected patients. Although famciclovir will not cure genital herpes or herpes zoster, it does help relieve the pain and discomfort and helps the sores heal faster.

This medicine is available only with your doctor's prescription.

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Proper UseTOP

Famciclovir is best used within 48 hours after the symptoms of shingles (for example, pain, burning, blisters) begin to appear, or within 6 hours after the symptoms of recurrent genital herpes (for example, pain, blisters) begin to appear.

Famciclovir may be taken with or without food.

To help clear up your herpes infection, keep taking famciclovir for the full time of treatment, even if your symptoms begin to clear up after a few days. Do not miss any doses and do not use this medicine more often or for a longer time than your doctor ordered.

DosingTOP

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

For oral dosage form (tablets):
- For treatment of shingles:
  - Adults—500 milligrams (mg) every eight hours for seven days.
  - Children—Use and dose must be determined by your doctor.
- For suppression of recurrent genital herpes:
  - Adults—250 milligrams (mg) two times a day for up to one year.
  - Children—Use and dose must be determined by your doctor.
- For treatment of recurrent genital herpes:
  - Adults—1000 milligrams (mg) two times a day for one day.
  - Children—Use and dose must be determined by your doctor.
- For treatment of recurrent herpes labialis (cold sores):
  - Adults—1500 milligrams (mg) as a single dose.
  - Children—Use and dose must be determined by your doctor.
- For treatment of recurrent herpes infections in HIV-infected patients:
  - Adults—500 milligrams (mg) two times a day for seven days.
  - Children—Use and dose must be determined by your doctor.

Missed DoseTOP

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Use & StorageTOP

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Before UsingTOP

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

AllergiesTOP

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

PediatricTOP

No information is available on the relationship of age to the effects of famciclovir in children under 18 years of age. Safety and efficacy have not been established.

GeriatricTOP

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of famciclovir in the elderly. However, elderly patients are more likely to have age-related kidney disease, which may require an adjustment of dose in patients receiving this medicine.

PregnancyTOP

	Pregnancy Category	Explanation
All Trimesters	B	Animal studies have revealed no evidence of harm to the fetus, however, there are no adequate studies in pregnant women OR animal studies have shown an adverse effect, but adequate studies in pregnant women have failed to demonstrate a risk to the fetus.

Breast FeedingTOP

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug InteractionsTOP

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Other InteractionsTOP

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

PrecautionsTOP

If your symptoms do not improve within a few days, or if they become worse, check with your doctor.

The areas affected by herpes should be kept as clean and dry as possible. Also, wear loose-fitting clothing to avoid irritating the sores (blisters).

This medicine may cause some people to become dizzy, drowsy, or less alert than they are normally. If any of these side effects occur, do not drive, use machines, or do anything else that could be dangerous if you are dizzy or are not alert while you are taking famciclovir.

This medicine does not prevent the sexual transmission of genital herpes. You should avoid having sex when lesions are present to avoid infecting your partner.

Chemical ClassificationsTOP

Guanosine Nucleoside Analog