Famvir is used for:

Treating herpes zoster infection (shingles). It is also used to treat recurring herpes skin infections in patients who also have HIV infection. Famvir is used in patients who have a weakened immune system to treat recurring cold sores and to treat or suppress recurring genital herpes. It may also be used for other conditions as determined by your doctor.

Famvir is an antiviral. It works by blocking reproduction of the virus.

Do NOT use Famvir if:

you are allergic to any ingredient in Famvir or to penciclovir
you have galactose intolerance, severe lactase deficiency, or glucose-galactose absorption problems

Contact your doctor or health care provider right away if any of these apply to you.

Before using Famvir :

Some medical conditions may interact with Famvir . Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:
if you are pregnant, planning to become pregnant, or are breast-feeding
if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
if you have allergies to medicines, foods, or other substances
if you have kidney problems

Some MEDICINES MAY INTERACT with Famvir . However, no specific interactions with Famvir are known at this time.

Ask your health care provider if Famvir may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use Famvir :

Use Famvir as directed by your doctor. Check the label on the medicine for exact dosing instructions.
Take Famvir by mouth with or without food. If stomach upset occurs, take with food to reduce stomach irritation.
If you are treating genital herpes or cold sores, start using Famvir at the first sign of an outbreak or cold sore as directed by your doctor.
If you are treating shingles, cold sores, genital herpes, or herpes skin infection, take Famvir for the full course of treatment. Keep taking it even if you feel better in a few days.
If you are using Famvir to suppress genital herpes, continue to take Famvir even if you feel well. Do not miss any doses.
If you miss a dose of Famvir , take it as soon as possible. If it is almost time for your next dose, skip the missed dose. Go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use this medicine.

Important safety information:

Famvir may cause drowsiness, dizziness, or blurred vision. These effects may be worse if you take it with alcohol or certain medicines. Use Famvir with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
Genital herpes patients - Famvir is not a cure for genital herpes. It will not prevent the infection from spreading the virus to others. To decrease the chance of infecting your partner, do not have sexual intercourse when sores are present. It may also be possible to spread the virus even if you do not currently have signs or symptoms of herpes. Discuss any questions or concerns with your doctor.
Use Famvir with caution in the ELDERLY; they may be more sensitive to its effects, especially delirium, disorientation, and confusion.
Famvir should be used with extreme caution in CHILDREN younger than 18 years old; safety and effectiveness in these children have not been confirmed.
PREGNANCY and BREAST-FEEDING: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Famvir while you are pregnant. It is not known if Famvir is found in breast milk. If you are or will be breast-feeding while you use Famvir , check with your doctor. Discuss any possible risks to your baby.

Possible side effects of Famvir :

All medicines may cause side effects, but many people have no, or minor side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Diarrhea; gas; headache; tiredness; vomiting.
Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); change in the amount of urine produced; confusion; delirium; disorientation; hallucinations; red, swollen, blistered, or peeling skin.