Famvir (Famciclovir)

What Famvir is and what it is used for

Famvir is an antiviral medicine. It stops the virus causing the infection from reproducing. Because the virus reproduces very early in the infection, treatment works best if you take Famvir as soon as the first symptoms appear.

Famvir is used in adults to treat shingles (herpes zoster) and recurrent genital herpes outbreaks. Famvir is not a cure for herpes infections.

Shingles (herpes zoster)

Shingles (herpes zoster) is a viral infection caused by the varicella zoster virus, the same virus that causes chickenpox.

The safety and effectiveness of Famvir for shingles affecting the eye(s) (ophthalmic zoster) have not been established.

Genital herpes

Genital herpes is a viral infection caused by herpes simplex virus type 1 or 2. It is usually spread through sexual contact. It causes blisters and burning or itching around the genitals, which can be painful.

Famvir is used to treat recurrent genital herpes outbreaks in adults. People who have frequent genital herpes outbreaks can also take Famvir as suppressive therapy to help reduce the number of outbreaks. The safety and effectiveness of suppressive therapy beyond 1 year have not been established.

Before you take Famvir

Do not take Famvir

If you are allergic (hypersensitive) to famciclovir, any of the ingredients in Famvir, or penciclovir (for example, Denavir® (penciclovir cream)). Ask your doctor for advice if you think you may be allergic.

Take special care with Famvir

• If you have kidney problems, or have had them in the past, your doctor may decide to give you a lower dose of Famvir.
• If you have problems with your immune system
• If you have liver problems

​​​​​​​If any of these apply to you, tell your doctor before you take Famvir.

Children and adolescents (below the age of 18 years)

Famvir is not recommended for children and adolescents.

Prevent passing genital herpes to others

If you are taking Famvir to treat or suppress genital herpes, or if you have had genital herpes in the past, you should still practise safer sex, including using condoms. This is important to help reduce the risk of passing the infection on to others. You should not have sex if you have genital sores or blisters.

Taking other medicines

Please tell your doctor or pharmacist if you are taking, or have recently taken, any other medicines, including medicines obtained without a prescription.

It is especially important to tell your doctor or pharmacist if you take probenecid, as it may increase penciclovir levels.

Taking Famvir with food and drink

You can take Famvir with or without food.

Pregnancy and breast-feeding

Ask your doctor or pharmacist for advice before taking any medicine.

If you are pregnant or planning to become pregnant, tell your doctor. It is not known whether Famvir will harm your unborn baby.

If you are breast-feeding or planning to breastfeed, tell your doctor. It is not known whether Famvir passes into breast milk or how it may affect a breastfed baby.

Driving and using machines

Famvir can cause dizziness, drowsiness or confusion. Do not drive or use machines if you have any of these symptoms while taking Famvir.

Important information about some of the ingredients of Famvir

If your doctor has told you that you have an intolerance to some sugars, such as lactose, contact your doctor before taking this medicine. Famvir 125 mg, 250 mg and 500 mg tablets contain lactose.

How to take Famvir

Always take Famvir exactly as your doctor has told you. Check with your doctor or pharmacist if you are not sure.

The daily dose and length of treatment will depend on the type of viral infection you have - see below. Your doctor will prescribe the right dose for you.

For the best results, start taking the medicine as soon as possible after the first signs and symptoms appear.

Do not have sexual contact with anyone if you have symptoms of genital herpes, even if you have started treatment with Famvir. This is because you could pass the herpes infection on to your partner.

If you have or have had kidney problems, your doctor may decide to give you a lower dose of Famvir.

Dose for shingles

If you have a normal immune system, the recommended dose is one 500 mg tablet three times a day for seven days.

Dose for genital herpes

The dose depends on the stage of your infection.

Famvir is not indicated for the first outbreak of genital herpes.

To treat recurrent outbreaks, the recommended dose is: 1000 mg twice daily for 1 day.

To help prevent future outbreaks (suppressive therapy), the recommended dose is one 250 mg tablet twice a day. Your doctor will tell you how long you need to keep taking your tablets.

The safety and effectiveness of Famvir have not been established in immunocompromised patients, except for treatment of recurrent orolabial or genital herpes in HIV-infected adults (500 mg twice daily for 7 days).

If you take more Famvir than you should

If you have taken more tablets than you were told to take, or if someone else accidentally takes your medicine, contact your doctor or go to hospital straight away for advice. Take the pack of tablets with you.

Taking too much Famvir may affect the kidneys. In people who already have kidney problems, it may rarely lead to kidney failure if the dose is not reduced correctly.

If you forget to take Famvir

If you miss a dose of Famvir, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and take your next dose at the usual time. Do not take two doses at the same time to make up for a missed dose.

If you have any further questions about using this product, ask your doctor or pharmacist.

Possible side effects

Like all medicines, Famvir can cause side effects, although not everybody gets them.

The most common side effects reported are headache and nausea.

Serious side effects of Famvir are:

• Severe blistering of the skin or mucous membranes of the lips, eyes, mouth, nasal passages or genitals (these could be signs of a serious allergic skin reaction).
• Unexplained bruising, reddish or purplish patches on the skin, or nosebleeds (these could be signs of a decrease in the number of blood platelets).

Contact a doctor or go to A&E straight away if you get any of these effects.

• Headache
• Feeling sick (nausea)
• Vomiting
• Dizziness
• Drowsiness
• Rash
• Itching

If any of the side effects become serious, or if you notice any side effects not listed in this leaflet, tell your doctor or pharmacist.

How to store Famvir

Keep out of the sight and reach of children.

Do not use Famvir after the expiry date shown on the label. The expiry date refers to the last day of that month.

Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F).

Do not use Famvir if you notice that the pack is damaged or shows signs of tampering.

Do not throw medicines away via wastewater or household waste. Ask your pharmacist how to dispose of medicines you no longer need. These measures will help protect the environment.