Famciclovir

Famciclovir is an antiviral medicine that is used to treat viruses in the herpes family including, herpes zoster that causes shingles, (a painful rash on the body) and herpes simplex that causes infections around the mouth (cold sores), anus, and genitals (genital herpes). It does not cure these infections but reduces the symptoms and the length of time you have them. In people who have frequent outbreaks, it can also reduce how often you have outbreaks.

Famciclovir tablets should be swallowed whole with water and can be taken with or without food. One tablet contains 125, 250, or 500mg, of the active ingredient Famciclovir. The dose and frequency of Famciclovir varies depending on your diagnosis, whether this is your first outbreak, and general health condition, so it is important that you take Famciclovir exactly as your doctor tells you. Famciclovir works best if you start taking it at the first sign of symptoms.

Normal dosage in immunocompetent patients (patients with a functioning immune system)

For herpes zoster (shingles) the dose is normally 500mg three times a day for 7 days, with the first dose given within 72 hours of the onset of symptoms.

For genital herpes the dose is normally 250mg 3 times a day for 5, followed by suppressive therapy of 250mg twice a day for up to 12 months. Recurrent episodes are normally treated with 1000mg twice a day for 1 day, at the first sign of symptoms (within 6 hours).

Normal dosage for immunocompromised patients (patients with a weakened immune system)

Immunocompromised patients, such as people with HIV, are normally treated with 500mg twice a day as suppressive therapy to prevent reactivation of the herpes simplex virus (HSV).

Famciclovir is a prodrug. It works by changing into the active antiviral agent penciclovir that stops the virus from reproducing inside the body. This controls the spread of the virus and allows your immune system to fight it. Famciclovir has a short half life (half the time it takes for the medicine to leave your body) of around two and a half hours.

Although it does not cure herpes, a 2012 review concluded that treatment of genital herpes with Famciclovir significantly reduced the length and severity of symptoms and increased the time between outbreaks. A further review on the treatment of shingles with Famciclovir found it to be the only oral antiviral treatment to significantly reduce the duration of post-herpetic neuralgia (PHN), the most serious side effect of shingles that causes pain and burning sensations in the nerves and skin. A Clinical trial on famciclovir and cold sores found that patients treated with famciclovir had a reduced healing time of two days compared to those given a placebo (false medication). It can take up to 10 days for herpes symptoms to clear up even when taking medication.

Common adverse effects include:

• headache
• nausea (feeling sick)
• diarrhoea
• abdominal pain
• dizziness

These are usually mild and not serious, but if they continue for a long time or get worse, speak to your healthcare provider.

Less common side effects include:

• mental changes or changes in mood such as confusion, agitation, dizziness, or drowsiness
• somnolence (feeling extremely drowsy and ready to fall asleep)
• angioedema (swelling of the face and neck)

Rare side effects include:

• thrombocytopaenia (a purplish rash or blotches on the skin)
• hallucinations
• palpitations (fast or irregular heart rate)
• cholestatic jaundice (yellowing or itching of the skin)
• anaphylactic shock is a severe allergic reaction that presents as difficulty breathing, swelling of the face and neck, skin rash, vomiting, fainting, dizziness, and fast heart rate. *This is an emergency and you need to call an ambulance
• seizures (fits)
• serious skin reactions

If you have any of these symptoms, seek medical advice from your doctor, pharmacist, or healthcare provider immediately.

Famciclovir may not be safe for some people. Your doctor will ask you some questions before prescribing Famciclovir. You should tell your doctor if you

• are allergic to Famciclovir, Penciclovir, or any other antiviral medication
• have a history of kidney problems
• have liver problems
• are under 18
• are pregnant or breastfeeding

Famciclovir does not normally react with other medicines but be sure to tell your doctor about any other medicines you are taking including herbal remedies and supplements. It is recommended that you don't drink alcohol or use marijuana while taking Famciclovir as this can make some of the side effects worse.

In addition to Famciclovir, there are other antiviral medications available that work in a similar way. In addition, some natural remedies, supplements, and changes to your diet may help relieve symptoms or help the body`s immune system fight the infection.

Other antiviral treatments include:

• Aciclovir (Zovirax)
• Valaciclovir (Valtrex)

These medicines are very similar to and work in similar ways to Famciclovir but have slightly different side effects. In severe herpes infection, or in immunocompromised patients, Aciclovir may be given IV (into a vein). Your doctor will decide which medicine is best for you.

Some topical (applied to the skin) treatments include:

• cold compress. An ice pack wrapped in a clean cloth can help reduce swelling. Remember never to apply ice directly to the skin
• baking soda or cornstarch paste. Dip a wet cotton ball or q-tip into baking soda or corn starch and apply to the sores (lesions)
• aloe vera gel, available from pharmacies (or if possible straight from the plant) can cool the lesions and reduce itching
• cool tea bags (especially camomile tea) applied to the lesions can help with itching and swelling. The tannin in tea may also have anti viral properties

Changes to your diet

Making changes to your diet can boost your immunity and reduce inflammation allowing your body to fight infection more effectively. Making changes to your diet could also help prevent future herpes outbreaks.

Eat plenty of:

• vegetables. Foods rich in antioxidants like cauliflower, kale, spinach, and tomatoes, can help boost your immune system
• foods containing omega-3 fatty acids like salmon, mackerel, chia seeds, and flaxseeds reduce inflammation and strengthen your immune system
• protein is important to help your body heal. Eat foods like nuts, eggs, chicken, and fish
• vitamin C has been shown to speed the healing of herpes blisters and lengthen the amount of time between outbreaks
• Zinc may help boost your immune system. Foods high in zinc include oysters, red meat and poultry, beans, nuts, and fortified cereals
• B Vitamins may also give your immune system a boost and can be found in leafy green vegetables like spinach and kale, dairy products like milk and cheese, eggs, chicken, and red meat

Some foods may make it harder for your body to fight the herpes virus or may make your symptoms worse.

Avoid:

• acidic foods like citrus fruits, fruit juices, wine, vinegar, and some salad dressings may break open cold sore blisters before they are healed and cause irritation

Other things you can do when you have an outbreak of herpes include:

• get lots of rest and avoid stress
• keep lesions clean and dry at all times
• if you have a cold sore, don’t share cups and avoid touching the sore
• if you have genital herpes wear loose-fitting clothing below the waist, avoid hot baths, and do not have sex until the lesions have healed
• if you have pain or discomfort you can take painkillers such as ibuprofen and paracetamol in addition to Famciclovir

How long does Famciclovir take to work?

For genital herpes, Famciclovir works best (within 48 hours) if you take it as soon as you have symptoms of a herpes outbreak. If it is taken after 48 hours it may take longer to work. If untreated, herpes sores usually take two to four weeks to fully heal.

Treatment of cold sores with Famciclovir is usually a single dose treatment taken after the cold sore has appeared. Associated symptoms such as headache, fever, and pain usually go away in a few days, but the sore itself normally takes two to four weeks to heal completely.

Shingles symptoms (rash, pain, burning, itching, fever, and headache) normally begin to subside within 72 hours if Famciclovir is taken within 72 hours from the onset of symptoms.

Is Famciclovir better than Valaciclovir?

All three antiviral medications Aciclovir, Valaciclovir, and Famciclovir are highly effective in treating herpes symptoms. Your doctor will decide which one is right for you based on your symptoms, immune system, lifestyle, and overall health.

Why was Famciclovir discontinued?

The brand name for famciclovir, Famvir was discontinued in the US in August 2021. The Food and Drug Administration (FDA) states that this was not due to manufacturing, product quality, safety, or efficacy concerns. However generic versions of Famciclovir are still approved and available.

What is Famciclovir 250mg used for?

Famciclovir may be given at a lower dose of 250mg to prevent recurrence of outbreaks in people who have multiple recurrent episodes of herpes.

How long has Famciclovir been on the market?

Famciclovir was approved for use in the treatment of herpes zoster (shingles) in 1994 and later for the treatment of herpes simplex (cold sores and genital herpes)

Can Famciclovir be taken with ibuprofen?

Yes. It is safe to take ibuprofen while taking Famciclovir. As with all medications, make sure you read the patient information leaflet and take the medication correctly.

How much does Famciclovir cost?

You can see the cost of Famciclovir at the top of this page.