Famvir (famciclovir) is an antiviral drug. It slows the growth and spread of the herpes virus so that the body can fight off the infection. Famciclovir will not cure herpes, but it can lessen the symptoms of the infections.
Famvir is used to treat infections caused by herpes viruses, including genital herpes, cold sores, and shingles.
There is no cure for herpes and Famvir will not prevent you from developing symptoms in the future.
Famvir may also be used for purposes not listed in this medication guide.
Important information
You should not take Famvir if you are allergic to famciclovir or penciclovir cream (Denavir). Take this medicine for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared.
Treatment with Famvir should be started as soon as possible after the first appearance of symptoms (such as tingling, burning, blisters).
Herpes infections are contagious and you can infect other people, even while you are being treated with Famvir. Avoid letting infected areas come into contact with other people. Avoid touching an infected area and then touching your eyes. Wash your hands frequently to prevent passing the infection to others.
Before taking this medicine
You should not take Famvir if you are allergic to famciclovir or penciclovir cream (Denavir).
To make sure you can safely take Famvir, tell your doctor if you have any of these other conditions:
FDA pregnancy category B. Famvir is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. Herpes virus can be passed from an infected mother to her baby during childbirth. If you have genital herpes, it is very important to prevent herpes lesions during your pregnancy so that you do not have a genital lesion when your baby is born. If you are pregnant, your name may be listed on a pregnancy registry. This is to track the outcome of the pregnancy and to evaluate any effects of Famvir on the baby. It is not known whether famciclovir passes into breast milk, or if it could harm a nursing baby. Do not take Famvir without telling your doctor if you are breast-feeding a baby. Do not give this medication to anyone under 18 years old without medical advice.
See also: Pregnancy and breastfeeding warnings (in more detail)
How should I take Famvir?
Take Famvir exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label. Taking more of this medication will not make it more effective
Treatment with Famvir should be started as soon as possible after the first appearance of symptoms (such as tingling, burning, blisters).
You may take Famvir with or without food.
Take this medicine for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. To prevent recurrent genital herpes, you may need to take this medicine twice daily for up to 1 year. Follow your doctor"s instructions.
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.
Store Famvir at room temperature away from moisture and heat.
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid?
Herpes infections are contagious and you can infect other people, even while you are being treated with Famvir. Avoid letting infected areas come into contact with other people. Avoid touching an infected area and then touching your eyes. Wash your hands frequently to prevent passing the infection to others.
Famvir will not prevent the spread of genital herpes. Avoid sexual intercourse or use a latex condom to prevent spreading the virus to others.
This medication may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.
Famvir side effects
Get emergency medical help if you have any of these signs of an allergic reaction to Famvir: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop using Famvir and call your doctor at once if you have a serious side effect such as:
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urinating less than usual or not at all;
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weakness, confusion, increased thirst, loss of appetite, vomiting, pounding heartbeats or fluttering in your chest; or
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swelling, weight gain, feeling short of breath.
Less serious Famvir side effects may include:
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nausea, gas, stomach pain;
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diarrhea,
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headache, tired feeling;
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dizziness, sleepiness;
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mild itching or skin rash; or
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numbness or tingly feeling.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
What other drugs will affect Famvir?
Tell your doctor about all other medicines you use, especially:
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probenecid (Benemid); or
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other medications you use to treat herpes outbreaks, such as acyclovir (Zovirax), valacyclovir (Valtrex), and others.
There may be other drugs that can interact with Famvir. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.
