Larotrectinib (Vitrakvi®) is used to treat different types of cancer. It can be used to treat cancers that have a change in a gene called NTRK. You have it if:
- the cancer is locally advanced or has spread to other parts of the body
- surgery to remove the cancer is likely to cause complications
- other treatment has not worked or is not suitable for you.
The gene change encourages the cancer cells to grow and divide. Larotrectinib blocks the effect of the gene change and slows or stops the cancer cell growth.
You have tests on the cancer cells to check for the gene change. This tells your doctor whether larotrectinib is likely to work for you.
Larotrectinib belongs to a group of targeted therapy drugs known as cancer growth inhibitors.
It is best to read this information with our general information about the type of cancer you have.
Your doctor will talk to you about this treatment and its possible side effects before you agree (consent) to have treatment.
Larotrectinib comes as capsules or sometimes as a liquid. So you can take it at home. During treatment, you usually see a cancer doctor, a cancer nurse or specialist nurse, and a specialist pharmacist. This is who we mean when we mention doctor, nurse or pharmacist in this information.
During treatment, you have regular blood samples taken to check things such as:
- the level of your blood cells
- how well your liver and kidneys are working.
Your doctor, nurse or pharmacist will discuss your treatment plan with you. They will explain how to take larotrectinib. They will give you the capsules or liquid to take home with you. Take all your medicines exactly as they have been explained to you.
You usually continue taking larotrectinib for as long as it is working.
Taking larotrectinib capsules
You usually take larotrectinib capsules twice a day. Try to take them at the same time each day. You can take them with or without food. Swallow the capsules whole with water. Do not chew, break or crush them.
If you forget to take the capsules, take your next dose at the usual time. Do not take a double dose.
Other things to remember about your capsules:
- Do not eat grapefruit or drink grapefruit juice while taking larotrectinib. This is because it may increase the amount of larotrectinib in your body.
- Keep your capsules safe and out of sight and reach of children.
- Keep them in the original package and at room temperature, away from heat and direct sunlight.
- If you are sick (vomit) just after taking the capsules, do not take another dose. Take your next dose at the usual time.
- If your treatment is stopped, return any unused capsules to the pharmacist.
We explain the most common side effects of this treatment here. We also include some less common side effects.
You may get some of the side effects we mention, but you are unlikely to get all of them. If you are also having treatment with other cancer drugs, you may have some side effects that we have not listed here. Always tell your doctor, nurse or pharmacist about any side effects you have.
Your doctor can give you drugs to help control some side effects. It is important to take them exactly as your nurse or pharmacist explains. This means they will be more likely to work for you. Your nurse will give you advice about managing your side effects. After your treatment is over, most side effects start to improve.
Serious and life-threatening side effects
Some cancer treatments can cause severe side effects. Rarely, these may be life-threatening. Your cancer doctor or nurse can explain the risk of these side effects to you.
Contact the hospital
Your nurse will give you telephone numbers for the hospital. If you feel unwell or need advice, you can call them at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.
We cannot list every side effect for this treatment. There are some rare side effects that are not listed. You can visit the electronic Medicines Compendium (eMC) for more detailed information.
Feeling tired is a common side effect of this treatment. It is often worse towards the end of treatment and for some weeks after it has finished. Try to pace yourself and plan your day so you have time to rest. Gentle exercise, like short walks, can give you more energy.
If you feel sleepy, do not drive or use machinery.
This treatment can cause constipation. Constipation means that you are not able to pass stools (poo) as often as you normally do. It can become difficult or painful. Here are some tips that may help:
- Drink at least 2 litres (3½ pints) of fluids each day.
- Eat high-fibre foods, such as fruit, vegetables and wholemeal bread.
- Do regular gentle exercise, like going for short walks.
If you have constipation, contact the hospital for advice. Your doctor can give you drugs called laxatives to help.
Effects on the nervous system
This treatment may affect the nervous system. This may make you feel dizzy or unsteady. Rarely, you may have tingling, numbness or a burning feeling in your hands and feet.
These side effects are more likely to happen during the first 3 months of treatment. But they may continue even after treatment is stopped. You should not drive or operate machinery until it is certain that you do not have these side effects. Contact the hospital straight away if you have any of these side effects.
Your doctor will give you anti-sickness drugs to help prevent or control sickness during your treatment. Take the drugs exactly as your nurse or pharmacist tells you. It is easier to prevent sickness than to treat it after it has started.If you feel sick, take small sips of fluids often and eat small amounts regularly. It is important to drink enough fluids. If you continue to feel sick, or are sick (vomit) more than once in 24 hours, contact the hospital as soon as possible. They will give you advice. Your doctor or nurse may change the anti-sickness drug to one that works better for you.
Muscle weakness or joint pain
Effects on the liver
This treatment may affect how your liver works. This is usually mild. You will have blood tests to check how well your liver is working.
Low number of white blood cells
This treatment can reduce the number of white cells in your blood. These cells fight infection. Tell your doctor or nurse if you have any signs of an infection. These include:
- a cough
- a sore throat
- needing to pass urine (pee) often.
Contact your doctor or the hospital straight away if:
- your temperature goes over 37.5°C (99.5°F)
- you suddenly feel unwell, even with a normal temperature
Anaemia (low number of red blood cells)
This treatment can reduce the number of red blood cells in your blood. Red blood cells carry oxygen around the body. If the number of red blood cells is low, this is called anaemia. You may have symptoms such as:
- pale skin
- lack of energy
- feeling breathless
- feeling dizzy and light-headed.
Tell your doctor or nurse if you have these symptoms.
If you are very anaemic, you may need a drip to give you extra red blood cells. This is called a blood transfusion.
Changes to your taste
You may get a bitter or metal taste in your mouth. Sucking sugar-free sweets may help with this. Some foods may taste different or have no taste. Try different foods to find out what tastes best to you. Taste changes usually get better after treatment finishes. Your nurse can give you more advice.
Blood clot risk
Cancer and some cancer treatments can increase the risk of a blood clot. Symptoms of a blood clot include:
- throbbing pain, redness or swelling in a leg or arm
- suddenly feeling breathless or coughing
- sharp chest pain, which may be worse when you cough or take a deep breath.
If you have any of these symptoms, contact the hospital straight away on the 24-hour contact number you have been given. If you cannot get through to your doctor, call the NHS urgent advice number on 111.
A blood clot is serious, but it can be treated with drugs that thin the blood (anticoagulants). Your doctor or nurse can give you more information.
You can help reduce the risk of developing a blood clot by:
- staying active during treatment
- drinking plenty of fluids, especially water.
You may be given anticoagulants to help prevent a clot.
Some medicines can affect how this treatment works or be harmful when you are having it. Always tell your cancer doctor about any drugs you are taking or planning to take, such as:
- medicines you have been prescribed
- medicines you buy in a shop or chemist
- vitamins, herbal drugs and complementary therapies.
Tell other doctors, pharmacists or dentists who prescribe or give you medicines that you are having this cancer treatment.
You can visit the electronic Medicines Compendium (eMC) for more detailed information about your treatment.
Vaccinations can reduce your risk of getting certain infections. Your doctor or nurse may talk to you about having vaccinations.
Doctors usually recommend that people with cancer have a flu vaccination and a coronavirus vaccination. These are both inactivated vaccinations that can help reduce the risk of infection. People with weak immune systems can have these, as they are not live vaccinations.
If your immune system is weak, you need to avoid live vaccinations. This is because they can make you unwell. Live vaccines, such as shingles, contain a very weak version of the illness they are vaccinating you against. Your cancer doctor or GP can tell you more about live and inactivated vaccinations.
You are advised not to breastfeed while having this treatment, or for some time after treatment finishes. This is because the drugs could be passed to the baby through breast milk.
Your doctor or nurse can give you more information.
Medical and dental treatment
If you need medical treatment for any reason other than cancer, always tell the doctors and nurses you are having cancer treatment. Give them the contact details for your cancer doctor so they can ask for advice.
If you think you need dental treatment, talk to your cancer doctor or nurse. Always tell your dentist you are having cancer treatment.
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert health professionals and people living with cancer.
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