Drug Name

Famvir (Famciclovir)

Drug Uses

Famvir is an oral antiviral prescription medication that is prescribed for: treatment of recurrent genital herpes in otherwise healthy patients; suppression of recurrent genital herpes in otherwise healthy patients; treatment of recurrent herpes simplex virus infections (genital herpes and cold sores) in HIV-infected patients and herpes zoster (shingles).

How Taken

Famvir can be prescribed in one of three ways: Episodic treatment: your doctor treats an outbreak of genital herpes as it occurs. The usual dose of Famvir is one 125-mg pill, twice a day, for 5 days. Suppressive treatment: if you have frequent or severe outbreaks, you take one 250-mg pill, twice a day, for up to 1 year to suppress the genital herpes virus and help to prevent outbreaks. Patients with HIV: Famvir is the only prescription oral antiviral therapy, indicated for treating genital. In patients with herpes simplex and HIV, the dose of Famvir is 500 mg, twice a day, for 7 days. Famvir can be taken with or without food.

Drug Class and Mechanism

Famciclovir is an antiviral drug which is active against the Herpes viruses, including herpes simplex 1 and 2 (cold sores and genital herpes) and varicella-zoster (shingles and chicken pox). It inhibits the replication of viral DNA that is necessary in order for viruses to reproduce themselves. Famciclovir is actually a "prodrug," in that it is not active directly against viruses. Instead, famciclovir is converted to penciclovir in the body, and it is the penciclovir that is active against the viruses. (Penciclovir also is available as a topical and intravenous medication.) Famciclovir is active against the same viruses as acyclovir but has a longer duration of action. Therefore, it can be taken fewer times each day. Famciclovir was approved for use by the FDA in 1994.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do NOT take 2 doses at once.

Storage

Store between 15C and 30C (59F and 86F) and out of the reach of children.

Warnings/Precautions

Do not take Famvir if you are allergic to penciclovir (Denavir) without first talking to your doctor. Before taking this medication, tell your doctor if you have kidney disease. You may need a dosage adjustment or special monitoring during treatment with Famvir. Famvir (Pregnancy Category B) should be used during pregnancy only if the benefit to the patient clearly exceeds the risk to the fetus.

Possible Side Effects

Stop taking Famvir and seek emergency medical attention if you experience an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives). Other, less serious side effects may be more likely to occur. Continue to take Famvir and talk to your doctor if you experience nausea or vomiting, headache, diarrhea, dizziness, tingling in your hands or feet, or itching.

More Information

Stop taking famciclovir and seek emergency medical attention if you experience an allergic reaction (difficulty in breathing; closing of your throat; swelling of your lips, tongue, or face; or hives). Other, less serious side effects may be more likely to occur. Continue to take famciclovir and talk to your doctor if you experience nausea or vomiting, headache, diarrhea, dizziness, tingling in your hands or feet, or itching. Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.