Filovir 125

Indications

Famciclovir is an antiviral medicine used to treat infections caused by herpes viruses. It is used for shingles (herpes zoster), for first and repeat episodes of genital herpes, for cold sores (herpes labialis), and to reduce how often genital herpes comes back in people who have frequent outbreaks.

How It Works

Famciclovir is a prodrug, which means the body converts it into its active form, Penciclovir. Inside cells infected with the herpes virus, Penciclovir blocks the enzyme the virus needs to copy its genetic material. This slows the spread of the virus, shortens the outbreak and eases pain. It does not remove the virus from the body completely, so outbreaks can return.

Dosage and Administration

Take by mouth with or without food. Start as soon as possible after symptoms appear, ideally within 72 hours for shingles and within 6 hours for cold sores or recurrent genital herpes. Usual adult doses:

• Shingles: 500 mg three times daily for 7 days.
• Recurrent genital herpes: 1000 mg twice daily for 1 day, or as prescribed.
• Cold sores: 1500 mg as a single dose.
• Suppression of genital herpes: 250 mg twice daily, as prescribed.

The dose must be reduced in people with kidney problems. Follow your doctor's instructions and finish the course.

Interactions

Probenecid may raise blood levels of Penciclovir. Tell your doctor about all medicines you take, including other antivirals and medicines that affect the kidneys. Raloxifene may reduce the conversion of Famciclovir to its active form.

Contraindications

Do not use if you are allergic to Famciclovir, Penciclovir or any ingredient of the product.

Side Effects

Common side effects include headache, nausea, diarrhoea, dizziness and tiredness. Less common effects include vomiting, stomach pain, rash, itching, confusion (more likely in older people) and changes in blood tests.

Get urgent medical help if you have a severe allergic reaction (swelling of the face or throat, difficulty breathing, widespread rash or blistering skin), severe confusion or hallucinations, or unusual bruising or bleeding.

Pregnancy and Lactation

There is limited information on use in pregnancy. Use only if your doctor decides the benefit outweighs the risk. It is not known whether it passes into breast milk, so ask your doctor before using it while breastfeeding.

Precautions and Warnings

Tell your doctor if you have kidney disease, as the dose needs adjusting. Genital herpes can still spread to a partner during treatment, so avoid sexual contact while sores are present. Dizziness or confusion may affect driving. Some tablets contain lactose.

Overdose

Overdose is unlikely to be serious in people with normal kidneys, but people with kidney problems may develop serious effects. Seek medical help if a large amount has been taken; dialysis can remove the drug.

Therapeutic Class

Antiviral (nucleoside analogue for herpes viruses).

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.