Famvir famciclovir

Famvir (Famciclovir)

Famvir is the brand name for Famciclovir a medicine that belongs to the group of antiviral medicines.   Antiviral medicines work by stopping the virus from growing and spreading, although they do not kill it off completely. More information

A doctor will review your order and write you a prescription, if appropriate. This prescription is then forwarded to a pharmacy. The pharmacy will have your medicine delivered to you within one to three working days. Read more about this process here.

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The herpes virus is responsible for several different kinds of problems, from cold sores and genital herpes caused by the herpes simplex virus to shingles and chickenpox caused by the varicella-zoster virus. These kinds of recurring illness can be extremely frustrating and over the counter medicines can treat the symptoms but never really attack the source of the problem. If you are looking for a solution that may do more to prevent frequent outbreaks then it is worth talking to your doctor to see what your options are. There are a number of antiviral medicines which can help to inhibit the herpes virus and stop it from spreading to relieve you of the unpleasant symptoms of outbreaks. 

What is Famvir-Famciclovir? 

Famvir is the brand name for Famciclovir a medicine that belongs to the group of antiviral medicines.  

Antiviral medicines work by stopping the virus from growing and spreading, although they do not kill it off completely. 

This particular antiviral medicine is active against the Herpes viruses, herpes simplex 1 and 2 (oral and genital herpes) and varicella-zoster (shingles and chickenpox) 

Famciclovir works by stopping the spread of the herpes virus in the body. It does this by preventing the virus from replicating so it cannot multiply. 

Famciclovir is converted in the body to penciclovir and it is this form which acts to inhibit the virus, because of this Famciclovir acts for longer than some other antivirals like acyclovir or valaciclovir meaning you won’t need to take Famvir as frequently during the day. This can be helpful for people with busy schedules. 

When is Famvir-Famciclovir used? 

Famvir is used to treat two types of viral infection in adults: 

  • Shingles caused by varicella-zoster, the same virus that causes chickenpox. Famvir stops the virus from spreading in the body so that healing can occur faster; 
  • Genital herpes caused by the herpes simplex virus. Symptoms include burning and itching around the genitals along with potentially painful blisters. Famvir is also used to prevent frequent attacks of genital herpes. 

How do you use Famvir-Famciclovir? 

Famvir comes in tablet form in a variety of strengths 125mg, 250mg and 500mg. The tablets are film-coated to make them easy to take. Always follow the instructions of your doctor when it comes to taking any medication. 

  • For best results start the medicine as soon as possible once symptoms appear; 
  • Swallow the tablet whole with water, you can take it with or without food; 
  • If you have genital herpes avoid sexual contact, even if you have started treatment as you can still pass the virus on you your partner. 

What dosages are there? 

The daily dose and the length of treatment required will depend on the type of virus you have. Your doctor will prescribe the correct dose so always follow their instructions if you are unsure check with the doctor or pharmacist. 

As a guide the dose for shingles is: 

  • 500mg three times a day for seven days if you have a normal immune system; 
  • 500mg three times a day for ten days is you have a reduced immune system. 

The guide dosage for genital herpes depends on the state of your immune system and how far developed the infection is. 

If you have a normal immune system the dose is: 

  • 250mg three times a day for five days for the first outbreak; 
  • 125mg twice a day for five days to treat further outbreaks; 
  • 250mg twice a day to prevent further outbreaks. Continue taking this dosage for as long as your doctor tells you to. 

If you have a reduced immune system the dosage is: 

  • 500mg twice a day for seven days to treat the current outbreak; 
  • 500mg twice a day to prevent future outbreaks. Continue taking this dosage for as long as your doctor tells you to. 

It is important you take your medicine regularly if you want to inhibit the virus and control your symptoms. It can help to set an alarm to remind yourself to take the medication at the right time of day, you should try to take your tablet at the same time each day. 

If you forget to take your tablet, take it as soon as you remember unless it is almost time for the next dose, then skip the tablet you have forgotten and carry on as normal. 

Never take a double dose to make up for a missed dose. 

Famvir is most effective when taken as soon as symptoms start to occur, missing a dose can give the virus a chance to thrive so try to time your medication to suit your schedule. 

What are the side effects of Famvir-Famciclovir? 

As with all medication, Famvir comes with the possibility of some side effects, not everyone who takes Famvir will experience the side effects. If you find the side effects very difficult to cope with then speak to your doctor as they may be able to offer advice for coping with the side effects or be able to offer you a different medicine if necessary. 

The most serious side effects are: 

  • Severe blistering of the skin or nose, lips, eyes, mouth or genitals (any of these could be a sign of an allergic skin reaction); 
  • Swelling below the surface of the skin (facial swelling, swelling around the eye and eyelid, swelling of the throat); 
  • Unexplained bruising or red and purple looking patches on your skin, or nosebleeds (these could be a sign of a decrease in the number of blood platelets); 
  • Yellowing of the skin and/or eyes, (this is a sign of jaundice). 
  • The side effects listed above are either rare or uncommon meaning they affect between 1 and 100 people in every 10,000 people who take Famvir. 

Very common side effects (these affect more than 1 in 10 people): 

  • Headaches. 

Common side effects (these affect up to 1 in 10 people): 

  • Abdominal pain; 
  • Diarrhoea
  • Nausea; 
  • Vomiting; 
  • Dizziness; 
  • Itching; 
  • Rash; 
  • Abnormal test results on liver function test. 

Uncommon side effects (these affect up to 1 in 100 people): 

  • Drowsiness (usually in the elderly); 
  • Itchy rash (urticaria); 
  • Confusion. 

Rare side effects (these affect up to 1 in 1,000 people): 

  • Palpitations (uneven heartbeat); 
  • Hallucinations (seeing or hearing things that are not really there). 

The frequency of the following side effects is unknown due to a lack of available data: 

  • Seizures or fits; 
  • Purple skin patches, itching, burning (signs of inflamed blood vessels); 
  • Difficulty breathing or swallowing along with potential rash, itching, hives, wheezing or coughing, dizziness, light-headedness, changes in levels of consciousness, hypotension, red skin, swelling of the face and throat, blue coloured lips, tongue or skin - all signs of a severe allergic reaction. 

If you experience any of the side effects above stop taking Famvir and seek immediate medical assistance. 

When shouldn’t you use Famvir-Famciclovir? 

Do not take Famvir if you are allergic to famciclovir, penciclovir or any of the other ingredients listed on the packet. If you think there is a chance you may be allergic to any of these discuss this with your doctor before starting the treatment. 

Take special care when taking Famvir if any of the following apply: 

  • You have problems with your body’s immune system; 
  • You have or have ever had kidney problems – you may need to take a lower dose of Famvir; 
  • You have liver problems; 
  • You are under the age of 18  - Famvir is not recommended for children or teenagers; 
  • You are pregnant or breastfeeding – Famvir should be avoided during pregnancy and breastfeeding unless absolutely necessary, you can discuss this further with your doctor; 
  • Famvir can cause drowsiness, dizziness and confusion, do not drive or operate machinery if you experience any of these side effects while taking Famvir. 

Does Famvir-Famciclovir interact with other medications? 

As with all medications you need to be careful that you aren’t taking medicines that interfere with one another or cause further problems. Make sure you tell your doctor about any medication you are taking, including herbal supplements and vitamins, before starting treatment with Famvir. 

Pay particular attention to the following as they can lead to increased side effects when taking Famvir. 

  • Probenecid – used to treat high blood levels of uric acid associated with gout and to increase blood levels of penicillin-type antibiotics; 
  • Raloxifene – used to prevent and treat osteoporosis; 
  • Any medication that can affect your kidneys. 

Where can you buy Famvir-Famciclovir? 

You can buy Famvir from any reputable pharmacy, pick the pharmacy that is easiest for you. It could be an online pharmacy that delivers direct to your home or office or you may prefer to pick up your medicine at your local pharmacy where you can check any details with the pharmacist on duty. 

Can I get Famvir-Famciclovir without a prescription? 

No you cannot buy Famvir-famciclovir without a prescription. You will need to speak to a doctor who can examine you and take a look at your medical history and decide whether Famvir is the right treatment for you. You can visit your local surgery or you can make an appointment for an online consultation. 


Herpes Viruses Association (2020). About herpes simplex virus - Herpes Viruses Association. [online] Herpes Viruses Association. Available at: https://herpes.org.uk/frequently-asked-questions/herpes-simplex-virus/ [Accessed 3 Jan. 2020]. 

Novartis Pharmacueticals (2018). [online] Medicines.org.uk. Available at: https://www.medicines.org.uk/emc/files/pil.1431.pdf [Accessed 8 Jan. 2020]. 

Ogbru, O. (2018). famciclovir, Famvir: Drug Facts, Side Effects and Dosing. [online] MedicineNet. Available at: https://www.medicinenet.com/famciclovir/article.htm [Accessed 8 Jan. 2020]. 

University of Ilinois Chicago (2018). Famciclovir | Side Effects, Dosage, Uses, and More. [online] Healthline. Available at: https://www.healthline.com/health/famciclovir-oral-tablet#important-warnings [Accessed 8 Jan. 2020]. 

Assessed by:

Dr Imran Malik, General practitioner
Registration number: GMC: 4741365

Dr Imran Malik studied undergraduate medicine at King's College University in Central London and clinical studies at the prestigious King's College Hospital. He graduated with a MBBS degree in 2000 and went on to gain postgraduate memberships with the Royal Society of Medicine and also General Practice in 2006.