Famciclovir is used to treat infections caused by certain types of viruses. It treats shingles caused by herpes zoster. It also treats outbreaks of herpes simplex that cause cold sores around the mouth, sores around the anus, and genital herpes. In people with frequent outbreaks of genital herpes, famciclovir is used to help reduce the number of future episodes.
Famciclovir is an antiviral drug. However, it is not a cure for these infections. The viruses that cause these infections continue to live in the body even between outbreaks. Famciclovir decreases the severity and length of these outbreaks. It helps the sores heal faster, keeps new sores from forming, and decreases pain/itching. This medication may also help reduce how long pain remains after the sores heal. In addition, in people with a weakened immune system, famciclovir can decrease the risk of the virus spreading to other parts of the body and causing serious infections.

How to use Famvir Oral
Take this medication by mouth with or without food, usually 2 to 3 times a day or as directed by your doctor.
This medication works best when started at the first sign of an outbreak, as directed by your doctor. It may not work as well if you delay treatment.
Dosage is based on your medical condition and response to treatment.
This medication works best when the amount of drug in your body is kept at a constant level. Therefore, take this drug at evenly spaced intervals. To help you remember, take it at the same times each day.
Continue to take this medication until the full prescribed amount is finished. Do not change your dose, skip any doses, or stop this medication early without your doctor\'s approval.
Tell your doctor if your condition persists or worsens.

Headache, nausea, and diarrhea may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor immediately if any of these unlikely but serious side effects occur: mental/mood changes (such as agitation, slowed thinking, confusion, hallucinations), dizziness, drowsiness.
Tell your doctor immediately if any of these rare but serious side effects occur: change in the amount of urine, yellowing eyes/skin, easy bruising/bleeding.
A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking famciclovir, tell your doctor or pharmacist if you are allergic to it; or to penciclovir; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney problems.
This drug may rarely make you dizzy or drowsy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages.
This medication may contain lactose. If you have certain conditions such as galactose intolerance, severe lactase deficiency (not lactose or milk intolerance), or glucose-galactose malabsorption that require you to restrict your intake of lactose, consult your doctor or pharmacist before taking this medication.
Kidney function declines as you grow older. This medication is removed by the kidneys. Older adults may be more sensitive to the side effects of this drug, especially dizziness, drowsiness, confusion, and change in the amount of urine.
Famciclovir does not protect against the spread of genital herpes. To lower the chance of giving herpes to your partner, do not have sexual contact during an outbreak or if you have symptoms. You can spread genital herpes even if you do not have symptoms. Therefore, always use an effective barrier method (latex or polyurethane condoms/dental dams) during all sexual activity. Consult your doctor or pharmacist for more details.
During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.
It is not known if this medication passes into breast milk. It may have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.

The effects of some drugs can change if you take other drugs or herbal products at the same time. This can increase your risk for serious side effects or may cause your medications not to work correctly. These drug interactions are possible, but do not always occur. Your doctor or pharmacist can often prevent or manage interactions by changing how you use your medications or by close monitoring.
To help your doctor and pharmacist give you the best care, be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products) before starting treatment with this product. While using this product, do not start, stop, or change the dosage of any other medicines you are using without your doctor\'s approval.
Keep a list of all the products you use. Share the list with your doctor and pharmacist to reduce your risk for serious medication problems.

If overdose is suspected, contact your poison control center or emergency room immediately. US residents can call the US National Poison Hotline at 1-800-222-1222. Canada residents can call a provincial poison control center.

NOTES:
Do not share this medication with others.
This medication has been prescribed for your current condition only. Do not use it later for another infection unless your doctor directs you to do so. A different medication may be necessary in that case.

MISSED DOSE:
If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

STORAGE:
Store at room temperature at 77 degrees F (25 degrees C) away from light and moisture. Brief storage between 59-86 degrees F (15-30 degrees C) is permitted. Do not store in the bathroom. Keep all medicines away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
Information last revised May 2010. Copyright(c) 2010 First Databank, Inc.