Vandetanib (Caprelsa) | Cancer Research UK
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Vandetanib (Caprelsa)

This page tells you about the biological therapy drug vandetanib and its possible side effects. There is information about


What vandetanib is

Vandetanib is pronounced van-det-ah-nib. It also has the brand name Caprelsa.

Vandetanib is a treatment for advanced medullary thyroid cancer. You may also have it as part of a clinical trial for other types of cancer.


How vandetanib works

Vandetanib is a type of biological therapy. It is a cancer growth blocker, which stops signals (chemical messengers) that cancer cells use to divide and grow. 


How you have vandetanib

Vandetanib is a tablet that you swallow whole once a day with water. You can choose the best time to take it. But you should take it at about the same time every day. You may take the tablets with or without food. You usually carry on taking vandetanib for as long as it works.

If you find it difficult to swallow the tablets you can dissolve them in still water. Don’t use any other type of liquid. Drop the tablet into half a glass of water without crushing it. Stir it occasionally for up to 15 minutes until the tablet is broken into very small particles. Drink the liquid straight away. Then half fill the glass again and drink it to make sure you take the whole dose.

If you forget to take vandetanib at your regular time and less than 12 hours have passed, take it straight away. If more than 12 hours have passed, do not take the tablets. Take your next tablets at the usual time the next day.

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.

We've listed the side effects associated with vandetanib below. You can use the links to find out more about each side effect. Where there is no link, please go to our cancer drug side effects section or use the search box at the top of the page.


Common side effects

  • Diarrhoea affects more than 5 out of 10 people (50%) – drink plenty of fluids if you have diarrhoea. Tell your doctor or nurse if you are worried about how bad it is or if it continues for more than 3 days  
  • Skin and nail changes – you may have a rash, blistering, or red, dry, skin, which usually starts within 10 days. If it is severe, your doctors may reduce the dose or stop treatment
  • Feeling or being sick happens in about 3 out of 10 people (30%) but is usually well controlled with anti sickness medicines
  • High blood pressure affects about 3 out of 10 people (30%) and your nurse or doctor will check your blood pressure regularly. You may start blood pressure tablets or may need to increase your dose if you are already taking them. Or you may need to stop vandetanib until your blood pressure is under control. Contact your doctor or nurse If you feel dizzy, faint, or have a headache
  • Changes in your heart rhythm – your doctor will ask you to have regular checks with electrocardiograms (ECGs) at the start of your treatment
  • Tiredness and weakness (fatigue) happens in up to 1 in 4 people (25%)
  • Headaches
  • Loss of appetite 
  • Sensitivity of the skin to sunlight – cover up with clothing and use sunscreen if you need to go out into the sun
  • Mood changes – you may feel sad or depressed
  • Difficulty sleeping
  • A cough and swelling and soreness of the lining of your nose, lungs and voice box
  • Blurred vision and other eye changes such as sore and red eyes (conjunctivitis)
  • An increased risk of getting an infection from a drop in white blood cells – it is harder to fight infections and you can become very ill. You may have headaches, aching muscles, a cough, a sore throat, pain passing urine, or you may feel cold and shivery. If you have a severe infection this can be life threatening. Contact your treatment centre straight away if you have any of these effects or if your temperature goes above 38°C.
  • Low calcium levels in the blood – let your nurse or doctor know if you have painful muscle spasms and cramps or twitching. Also tell them if you have any numbness or tingling in your feet and hands or around the mouth
  • Indigestion, stomach pains or discomfort
  • Numbness and tingling of your skin
  • Fluid build up that may cause ankle and finger swelling (or weight gain)

Occasional side effects

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

  • Changes in your blood chemistry – the levels of potassium, sodium and glucose may be higher or lower than normal. You may not have any symptoms from this
  • A sore mouth
  • Taste changes
  • Hair loss
  • Anxiety
  • Gallstones
  • Soreness, redness and peeling of the palms of the hands and soles of the feet (palmar-plantar syndrome)
  • Difficulty passing urine or a need to pass it more often
  • Kidney problems, which are usually temporary – you will have regular blood tests to check how well your kidneys are working

Rare side effects

Fewer than 1 in 100 people have these effects.

  • Long term heart damage causing chest pain, swollen ankles, breathlessness and a fast heart rate – tell your doctor or nurse if you have any of these symptoms
  • Bruising more easily due to a drop in platelets – you may have nosebleeds, bleeding gums after brushing your teeth, or lots of tiny red spots or bruises on your arms or legs (known as petechia)
  • Bowel problems, including constipation, a blockage, or a split in the wall of the bowel (perforation) – this is rare but a serious side effect if it happens. Tell your doctor or nurse straight away if you have sudden severe tummy (abdominal) pain

Important things to remember

You may have a few side effects. They may be mild or more severe. A side effect may get better or worse through your course of treatment. Or more side effects may develop as the course goes on. This depends on

  • How many times you've had the drug before
  • Your general health
  • The amount of the drug you have (the dose)

The side effects may be different if you are having vandetanib with other drugs.

Tell your doctor or nurse straight away if any of the side effects get severe.

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 4 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.


Immunisations and vandetanib

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.


More information about vandetanib

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: 21 February 2014