Dabrafenib (Tafinlar) and Trametinib (Mekinist)

Dabrafenib and trametinib are types of targeted cancer drugs called cancer growth blockers. They are used together to treat:

  • melanoma skin cancer that can’t be removed with surgery (unresectable) or has spread to other areas of the body (metastatic or advanced melanoma)
  • stage 3 melanoma skin cancer that has been completely removed with surgery (to reduce the risk of the cancer coming back)
  • advanced non small cell lung cancer (NSCLC)

You can only have these drugs if your cancer has a change in the BRAF gene. Your doctor tests for this before you start treatment.

How dabrafenib and trametinib works

Dabrafenib and trametinib are types of cancer growth blockers. They work by targeting certain proteins that help cancer cells grow. By blocking these proteins, this combination of drugs stops or slows down the growth of cancer cells.

How you have dabrafenib and trametinib

You take trametinib as a tablet and dabrafenib as a capsule.

You swallow them whole with a full glass of water. You take them on an empty stomach. This means you take them at least 1 hour before a meal or 2 hours after a meal.

Taking your tablets or capsules

You must take tablets and capsules according to the instructions your doctor or pharmacist gives you.

You should take the right dose, not more or less.

Talk to your healthcare team before you stop taking a cancer drug, or if you have missed a dose.

When you have dabrafenib and trametinib

Usually you take dabrafenib twice a day, morning and evening, about 12 hours apart. You take trametinib only once a day.

For advanced cancer you take dabrafenib and trametinib for as long as they are working and the side effects aren’t too bad.

If you’re having this combination of drugs to prevent melanoma skin cancer coming back after surgery, you take them for up to 12 months.


You have regular blood tests, scans and other tests during this treatment. 

Your doctor or nurse will explain what tests you need.

Side effects

How often and how severe the side effects are can vary from person to person. They also depend on what other treatments you're having. 

When to contact your team

Your doctor, nurse or pharmacist will go through the possible side effects. They will monitor you during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:

  • you have severe side effects 
  • your side effects aren’t getting any better
  • your side effects are getting worse

Early treatment can help manage side effects better. 

Contact your advice line immediately if you have signs of infection, including a temperature above 37.5C or below 36C.

We haven't listed all the side effects here. Remember it is very unlikely that you will have all of these side effects, but you might have some of them at the same time.

Common side effects

These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:

High temperature or flu-like symptoms

Symptoms include a high temperature, sore throat, runny nose, headaches, muscle aches, shivering (chills), sneezing or coughing.

Let your doctor or nurse know if you have any of these symptoms or feel generally unwell.

Decreased appetite

You might have less of an appetite for various reasons when you are having cancer treatment. Sickness, taste changes or tiredness can all put you off food and drinks.

Headaches and dizziness

Let your doctor or nurse know if you have headaches. They can give you painkillers. Don’t drive or operate machinery if you feel dizzy.

High blood pressure (hypertension)

Tell your doctor or nurse if you have headaches, nosebleeds, blurred or double vision or shortness of breath. Your nurse will check your blood pressure regularly.


These drugs can cause bleeding from anywhere in your body. This is usually mild but there is a risk of a serious bleed. Signs of bleeding include blood in your urine or poo (stool), black stool, vomiting or coughing up blood, headaches, dizziness or feeling weak.

Contact your doctor or nurse straight away if you have any signs of bleeding.


Tell your doctor or nurse if you develop a cough. This could be due to an infection.

Tummy (abdominal) pain

Tell your doctor or nurse if you have this. They can check for the cause of the pain and give you medicine to help. 

Diarrhoea or constipation

Tell your healthcare team if you have diarrhoea or constipation. They can give you medicine to help. 

Feeling or being sick

Feeling or being sick is usually well controlled with anti sickness medicines. Avoiding fatty or fried foods, eating small meals and snacks, drinking plenty of water, and relaxation techniques can all help.

It is important to take anti sickness medicines as prescribed even if you don’t feel sick. It is easier to prevent sickness rather than treating it once it has started.

Skin problems

Symptoms of skin problems can include a rash, dry skin, itching and reddening of the skin. Less commonly your skin might be sensitive to the sun or develop wart-like growths.

Your doctor will check your skin regularly throughout your treatment.

Let your doctor or nurse know if you get any skin rash or a rash that gets worse, or you’re worried about any other changes to your skin.

Arm, leg, joint or muscle pain

You might feel some pain in your arms, legs, muscles or joints. Speak to your doctor or nurse about what painkillers you can take to help with this.

Muscle spasms

You may feel stiff and have muscle spasms. Let your doctor or nurse know if you have muscle spasms during or after having treatment.

Tiredness and weakness

Tiredness and weakness (fatigue) can happen during and after treatment. Doing gentle exercises each day can keep your energy up. Don't push yourself, rest when you start to feel tired and ask others for help.

Talk to your doctor or nurse if this effect is stopping you from doing your usual daily activities.

Swelling in the hands, feet and face

You may have swelling of your face, hands and feet due to a build up of fluid (oedema). 

Liver changes

You might have liver changes that are usually mild and unlikely to cause symptoms. They usually go back to normal when treatment finishes. You have regular blood tests to check for any changes in the way your liver is working.

Occasional side effects

These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:

  • risk of getting an infection – due to a drop in white blood cells that help fight against infection
  • low levels of red blood cells in your blood (anaemia), this can make you feel weak and tired
  • low levels of platelets – this can increase the risk of bleeding
  • infection such as water infection (urinary tract infection – UTI), deep skin infection (cellulitis) or inflammation of the hair follicles (folliculitis)
  • a different type of skin cancer called squamous cell carcinoma – this is usually removed with surgery
  • dehydration – signs include feeling dizzy, not passing much urine, and dark coloured urine
  • low levels of salts (sodium and phosphate) in your blood
  • high blood sugars
  • eye problems such as blurred vision, eye pain, flashes of light, floaters (tiny spots that appear in your vision) and redness in your eyes
  • heart problems including a drop in how well the heart pumps blood
  • low blood pressure – you might feel dizzy, lightheaded or faint
  • shortness of breath
  • a dry or sore mouth and you may have mouth ulcers
  • sweating more than usual or night sweats
  • hair thinning
  • sore, red and painful hands and feet
  • inflammation of tissue (mucosa) – the mucosa lines a number of different areas in the body such as your mouth, bowel and airways
  • an increased level of an enzyme in your blood that can be a sign of injury to muscle, including the heart

Rare side effects

These side effects happen in fewer than 1 in 100 people (fewer than 1%). You might have one or more of them. They include:

  • a new primary melanoma
  • an allergic reaction – you may get a rash, shortness of breath, redness or swelling of the face
  • inflammation of the lungs (pneumonitis)
  • inflammation of your pancreas – symptoms include severe tummy pain, feeling or being sick, a high temperature or you may have loose poo
  • inflammation of the bowel (colon) causing tummy pain, diarrhoea, fever, blood in your poo
  • kidney problems – your bloods may show your kidneys aren’t working properly, or symptoms might include confusion, not passing enough urine and shortness of breath

Coping with side effects

We have more information about side effects and tips on how to cope with them.

What else do I need to know?

Blood clots

Blood clots can develop in the deep veins of your body, usually the leg. This is called deep vein thrombosis (DVT). A blood clot can be very serious if it travels to your lungs (pulmonary embolism), although this isn’t common.

Symptoms of a blood clot include:

•    pain, redness and swelling around the area where the clot is and may feel warm to touch
•    breathlessness
•    pain in your chest or upper back – dial 999 if you have chest pain
•    coughing up blood

Tell your doctor immediately or go to A&E if you have any symptoms of a blood clot.

Other medicines, foods and drink

Cancer drugs can interact with some other medicines and herbal products. Tell your doctor or pharmacist about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies.

Grapefruit and grapefruit juice

You should not eat grapefruit or drink grapefruit juice when you are taking dabrafenib because it can react with the drug and make side effects worse.


You may not be able to become pregnant or father a child after treatment with this drug. Talk to your doctor before starting treatment if you think you may want to have a baby in the future. Men may be able to store sperm before starting treatment. Women may be able to store eggs or ovarian tissue but this is rare.

Pregnancy and contraception

This treatment may harm a baby developing in the womb. It is important not to become pregnant or father a child while you're having treatment with these drugs and for at least 4 months afterwards. Talk to your doctor or nurse about effective contraception before starting treatment.

This treatment may have an effect on how well hormonal contraceptives work. If you’re taking hormonal contraceptives like the pill, injections or patches you should use additional barrier contraceptives such as condoms.


It is not known whether this drug comes through into the breast milk. Doctors usually advise that you don’t breastfeed during this treatment.

Driving and use of machinery

These drugs can cause tiredness, dizziness and eye problems. Don’t drive or operate heavy machinery if you have these problems.

Treatment for other conditions

Always tell other doctors, nurses, pharmacists or dentists that you’re having this treatment if you need treatment for anything else, including teeth problems.


Don’t have immunisations with live vaccines while you’re having treatment and for up to 12 months afterwards. The length of time depends on the treatment you are having. Ask your doctor or pharmacist how long you should avoid live vaccinations.

In the UK, live vaccines include rubella, mumps, measles, BCG, yellow fever and one of the shingles vaccines called Zostavax.

You can have:

  • other vaccines, but they might not give you as much protection as usual
  • the flu vaccine (as an injection)
  • the coronavirus (COVID-19) vaccine - talk to your doctor or pharmacist about the best time to have it in relation to your cancer treatment

Members of your household who are aged 5 years or over are also able to have the COVID-19 vaccine. This is to help lower your risk of getting COVID-19 while having cancer treatment and until your immune system Open a glossary item recovers from treatment.

Contact with others who have had immunisations - You can be in contact with other people who have had live vaccines as injections. Avoid close contact with people who have recently had live vaccines taken by mouth (oral vaccines) such as the oral typhoid vaccine. Sometimes people who have had the live shingles vaccine can get a shingles type rash. If this happens they should keep the area covered.

If your immune system is severely weakened, you should avoid contact with children who have had the flu vaccine as a nasal spray as this is a live vaccine. This is for 2 weeks following their vaccination.

Babies have the live rotavirus vaccine. The virus is in the baby’s poo for about 2 weeks and could make you ill if your immunity is low. Get someone else to change their nappies during this time if you can. If this isn't possible, wash your hands well after changing their nappy.

More information about this treatment

For further information about this treatment go to the electronic Medicines Compendium (eMC) website.

You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.

This page is due for review. We will update this as soon as possible.

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