Famciclovir

Famciclovir is an antiviral medicine used to treat infections caused by herpes viruses, including genital herpes, cold sores, and shingles.

Famciclovir is sometimes used in people with human immunodeficiency virus (HIV) who have herpes outbreaks around the mouth, genitals, or anal area.

Famciclovir might not be effective in treating your first episode of genital herpes, but it may help prevent future episodes. Famciclovir may also not be effective in Black or African-American individuals with genital herpes, and it may not work for anyone with shingles (herpes zoster) affecting the eyes.

There is no cure for herpes, and famciclovir will not stop you from developing symptoms in the future.

Famciclovir may also be used for purposes not listed in this medication guide.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Taking more famciclovir than prescribed will not make this medicine more effective.

For cold sores or genital herpes, you should start taking famciclovir as soon as possible after the first signs of symptoms (such as tingling, burning, blisters).

You may take famciclovir with or without food.

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.

To prevent recurrent genital herpes, you may need to take famciclovir for up to 1 year. Follow your doctor's instructions.

Use this medicine for the full prescribed length of time, even if your symptoms quickly improve. Skipping doses may increase the risk of your virus becoming resistant to medication.

Store at room temperature away from moisture and heat.

Follow all instructions on your medicine label and package. Inform each of your healthcare providers about all your medical conditions, allergies, and all medicines you are using.

You should not use famciclovir if you are allergic to famciclovir or penciclovir cream (Denavir).

Tell your doctor if you have ever had:

• liver disease;
• kidney disease;
• a weak immune system;
• galactose intolerance;
• severe lactase deficiency; or
• glucose-galactose malabsorption.

Tell your doctor if you are pregnant or plan to become pregnant. Herpes can be passed to your baby during childbirth if you have a genital lesion when your baby is born. If you have genital herpes, it is very important to prevent herpes lesions during pregnancy. Take your medicine as directed to best control your infection.

If you are pregnant, your name may be listed on a pregnancy registry to track the effects of famciclovir on the baby.

It may not be safe to breast-feed while using this medicine. Ask your doctor about any risk.

Famciclovir is not approved for use by anyone younger than 18 years old.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Famciclovir may cause serious side effects. Call your doctor right away if you have:

• confusion; or
• kidney problems—little or no urination, swelling in your feet or ankles, feeling tired or short of breath.

Common side effects of famciclovir may include:

• headache; or
• nausea.

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 the FDA at 1-800-FDA-1088.

Usual Adult Dose for Herpes Simplex -- Mucocutaneous/Immunocompetent Host:

Genital herpes:Initial episode: 250 mg orally 3 times a day for 7 to 10 days has been recommended by the US Centers for Disease Control and Prevention (CDC)Recurrent episodes: 1000 mg orally twice a day for 1 day; alternatively, 125 mg orally twice a day for 5 days has been recommended by the CDCFamciclovir should be started at the first sign or symptom of a recurrent episode (such as tingling, burning, itching, pain, or lesion). The efficacy has not been established if started more than 6 hours after onset of symptoms or lesions.

Usual Adult Dose for Herpes Simplex -- Mucocutaneous/Immunocompromised Host:

Recurrent episodes of orolabial or genital herpes in HIV-infected patients: 500 mg orally twice a day for 7 days (5 to 10 days recommended by the CDC)Famciclovir should be started at the first sign or symptom of a recurrent episode (such as tingling, burning, itching, pain, or lesion). The efficacy has not been established if started more than 48 hours after onset of symptoms or lesions.

Usual Adult Dose for Herpes Simplex -- Suppression:

Chronic suppression of recurrent genital herpes:Immunocompetent patients: 250 mg orally twice a dayHIV-infected patients: 500 mg orally twice a day has been recommended by the CDCTherapy should be continued as clinically appropriate, although the safety and efficacy of famciclovir therapy beyond 1 year have not been established.

Usual Adult Dose for Herpes Zoster:

500 mg orally every 8 hours for 7 daysFamciclovir is most effective if started within 48 hours of onset of rash. The efficacy has not been established if started more than 72 hours after onset of rash.

Usual Adult Dose for Herpes Simplex Labialis:

Recurrent herpes labialis: 1500 mg orally as a single doseFamciclovir is most effective if started at the earliest sign or symptom of a cold sore (such as tingling, burning, itching, pain, or lesion).

Take the medicine as soon as you can, but skip the missed dose if it is close to the time for your next dose. Do not take two doses at the same time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Taking famciclovir will not stop you from passing genital herpes to others. Herpes infections are contagious, and you can infect others even while taking famciclovir.

Avoid driving or doing anything dangerous until you know how this medicine affects you. Your reactions might be affected.

Avoid sexual intercourse or use a latex condom to help prevent spreading the virus to others. Do not let infected areas touch other people. Avoid touching an infected area and then touching your eyes. Wash your hands often to stop the spread of infection.

Other drugs may affect famciclovir, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.