Famciclovir

What is Famciclovir?

Famciclovir is an antiviral medicine that treats the symptoms of genital herpes, a sexually transmitted infection (STI). Symptoms of genital herpes include small ulcers around your genitals, inflammation, and pain when urinating. Famciclovir works by inhibiting viral replication, which prevents the growth and spread of the virus. There’s no cure for genital herpes, but treating the infection early on can stop your symptoms from worsening.

How does Famciclovir work?

Famciclovir is an antiviral medicine that inhibits viral replication. When taken, it’s converted into penciclovir inside your body. With the help of an enzyme from the herpes virus, it turns penciclovir into ‘penciclovir monophosphate’. This form only affects infected cells, leaving the unaffected cells unharmed, making it a safe and efficient drug.

Penciclovir monophosphate is then converted again into ‘penciclovir triphosphate’. This is the active form that binds to the herpes virus DNA. The binding prevents the DNA from replicating, which inhibits viral replication and spread.

To summarise, Famciclovir converts into multiple forms until it becomes penciclovir triphosphate, where it binds to DNA, inhibiting viral replication.

What doses of Famciclovir are there?

There are 3 doses of famciclovir: 125 mg, 250 mg and 500 mg. The dosage differs based on how healthy your immune system is and the nature of your symptoms.

If you have a normal-functioning immune system, the dosage is listed below.

• For the first outbreak - 250 mg three times a day, for five days.
• To treat further outbreaks - 125 mg twice a day, for five days.
• To prevent future outbreaks - 250 mg twice a day, until your clinician tells you to stop.

Whereas if you have a weakened immune system, your dosage will differ.

• For the current outbreak -  500 mg twice a day, for seven days.
• To prevent future outbreaks - 500 mg twice a day, until your clinician tells you to stop.

How to take Famciclovir

Famciclovir should be taken as advised by our clinician. Depending on the outbreak, they’ll tell you what dose to take and how long to take it for. If you have a weakened immune system your dosage will be higher, but if you have kidney problems, your doctor will recommend a lower dose. To take Famciclovir, follow the directions below:

1. Start the medication as soon as you get symptoms.
2. Swallow the tablet whole with water. It can be taken with or without food.
3. If you’re taking it multiple times a day, make sure there's more than one hour between each dose. It’s preferable to take it in the morning, afternoon and evening.
4. If you have symptoms before and during treatment, don’t have sex with anyone until the infection clears. This is because you can spread the infection to your partner.

What should I do if I make a mistake when taking Famciclovir?

If you accidentally take more than the recommended dosage, ask your doctor for advice. Taking too much can affect your kidneys, especially if you have kidney problems.

If you forget to take a dose, take it as soon as you remember. Unless it's within 1 hour of your next dose, in that case, skip it. Don't take a double dose to make up for a missed one.