Vemurafenib (Zelboraf) | Cancer Research UK
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Vemurafenib (Zelboraf)

This page tells you about the biological therapy vemurafenib and its possible side effects. Vemurafenib is pronounced as vem-yoo-raf-en-ib. There is information about


What vemurafenib is

Vemurafenib is a type of biological therapy drug called a cancer growth blocker. It stops cells producing a protein called BRAF, which makes some cancer cells grow and divide. About half of all melanoma skin cancers make too much BRAF due to a change in a gene. The gene is called the BRAF gene.

Vemurafenib is a treatment for people with advanced melanoma whose cancer cells have a change in the BRAF gene. You have a test to check for the gene change before starting treatment with vemurafenib.

Vemurafenib is also known by its brand name Zelboraf.


How you have vemurafenib

Vemurafenib comes as tablets. You swallow them whole with a glass of water. 

You take vemurafenib twice a day, 12 hours apart. The normal dose is 4 tablets in the morning and 4 in the evening. It is best to take them with food or shortly after eating.

You usually carry on taking it for as long as it works unless the side effects get too bad.

It is very important that you take tablets according to the instructions your doctor or pharmacist gives you. For example, whether you have a full or empty stomach can affect how much of a drug gets into your bloodstream. You should take the right dose, not more or less. And never stop taking a cancer drug without talking to your specialist first.

The side effects associated with vemurafenib are listed below.


Common side effects

More than 10 in every 100 people have one or more of these effects

  • Sensitivity to sunlight happens in 5 out of 10 people (50%) – don’t sit out in the sun, and make sure you cover up or use sun block on exposed skin
  • Skin changes – about 3 out of 10 people (30%) have a rash or red, dry, itchy skin. It may get very sore in areas that have had radiotherapy
  • New skin cancers including squamous cell skin cancers happen in about a quarter of people (25%). Your doctor will check your skin during treatment and for 6 months afterwards. Let them know if you notice any skin changes between appointments. These can easily be removed if found early.
  • Loss of appetite
  • Headaches
  • Tiredness during and after treatment
  • Feeling or being sick happens in about 2 out of every 10 people (20%) but is usually well controlled with anti sickness medicines
  • Hair thinning occurs in just under 4 out of 10 people (40%)
  • Taste changes
  • Diarrhoea – drink plenty of fluids and tell your doctor or nurse if diarrhoea becomes severe, or continues for more than 3 days
  • Constipation – your doctor or nurse may give you laxatives to help prevent this. Drink plenty of fluids and tell your doctor or nurse if you are constipated for more than 3 days
  • Aching joints and muscle or bone pain
  • Pain in the hands and feet
  • Back pain
  • A high temperature for a few hours after the treatment
  • Swelling due to fluid build up, usually in the legs
  • Liver changes that are very mild and unlikely to cause symptoms – the liver will almost certainly go back to normal when treatment is finished. You will have regular blood tests to check how well your liver is working
  • A cough

Occasional side effects

Between 1 and 10 in every 100 people have one or more of these effects

  • Basal cell skin cancer or a new melanoma
  • Some people develop soreness, redness and peeling on the palms of the hands and soles of the feet (palmar–plantar syndrome),which may cause tingling, numbness, pain and dryness
  • Sore, inflamed eyes
  • Drooping of one side of your face (facial palsy)
  • Tingling or burning feeling in hands and feet, which can cause difficulty with fiddly things such as doing up buttons
  • Swollen, painful joints
  • Sore, red, skin around hair
  • Weight loss
  • Dizziness
  • Heart changes – you will have regular heart tests
  • Inflammation of fatty tissue under the skin

Rare side effects

Fewer than 1 in 100 people have one or more of the following effects.

  • An allergic reaction when the drug is given – let your doctor or nurse know straight away if you feel faint or have swelling of the face, lips or tongue or difficulty breathing
  • A severe skin reaction called Stevens-Johnson syndrome, which makes your skin become very painful and red. This redness spreads and blisters. The top layer of skin may fall off. Most people who have this reaction need to stop the treatment permanently and go into hospital to control the symptoms
  • Changes in the nerves that may cause pain and severe numbness
  • Eyesight changes due to blockage of blood going to the back of the eye
  • Redness and swelling of the blood vessels
  • Increased risk of cancer in areas of the body other than the skin – your doctor will check your head, neck, mouth and lymph nodes regularly. You will also have regular CT scans. Your doctor or nurse will examine the skin of your back passage before and at the end of your treatment. Women have an examination of the genital area
  • Stomach pain caused by inflammation of your pancreas (pancreatitis) – let your doctor or nurse know if you have sudden strong abdominal pains

Important points to remember

You will not get all these side effects and some of them may be mild. A side effect may get worse through your course of treatment. Or you may have more side effects as the course goes on. This depends on

  • How many times you've had a drug before
  • Your general health
  • How much of the drug you have (the dose)
  • Other medicines you are taking

Coping with side effects

Talk to your doctor, pharmacist or nurse about all your side effects so they can help you manage them. They can give you advice or reassure you. Your nurse will give you a contact number to ring if you have any questions or problems. If in doubt, call them.

Other medicines

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and over the counter remedies. Some drugs can react together.

Pregnancy and contraception

This drug may harm a baby developing in the womb. It is important not to become pregnant or father a child while you are having treatment with this drug and for at least 6 months afterwards. Talk to your doctor or nurse about effective contraception before starting treatment.


Do not breastfeed during this treatment because the drug may come through in the breast milk.



You should not have immunisations with live vaccines while you are having treatment or for at least 6 months afterwards. In the UK, these include rubella, mumps, measles (usually given together as MMR), BCG, yellow fever and Zostavax (shingles vaccine).

You can have other vaccines, but they may not give you as much protection as usual until your immune system has fully recovered from your treatment. It is safe to have the flu vaccine.

It is safe for you to be in contact with other people who've had live vaccines as injections. There can be problems with vaccines you take by mouth (oral vaccines), but not many people in the UK have these now. So there is usually no problem in being with any baby or child who has recently had any vaccination in the UK. You might need to make sure that you aren't in contact with anyone who has had oral polio, cholera or typhoid vaccination recently, particularly if you live abroad.


Related information


More information about vemurafenib

This page does not list all the very rare side effects of this treatment that are very unlikely to affect you. For further information look at the Electronic Medicines Compendium website at

If you have a side effect not mentioned here that you think may be due to this treatment you can report it to the Medicines Health and Regulatory Authority (MHRA) at

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Updated: 22 May 2014