Cladribine (Leustat® or LITAK®)

It is best to read our information about cladribine (Leustat® or LITAK) with our general information about chemotherapy and the type of cancer you have.

Your cancer doctor will talk to you about this treatment and its possible side effects before you agree (consent) to have treatment.

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.

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.

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.

This treatment can reduce the number of white blood cells in your blood. These cells fight infection. If the number of white blood cells is low, you are more likely to get an infection. A low white blood cell count is sometimes called neutropenia.

Your doctor may give you antibiotics and other drugs to try to stop you getting an infection. These are called prophylactic medicines.

An infection can be very serious when the number of white blood cells is low. It is important to get any infection treated as soon as possible. Contact the hospital straight away on the 24-hour contact number you have been given if:

• your temperature goes over 37.5°C (99.5°F) 
• you suddenly feel unwell, even with a normal temperature
• you have symptoms of an infection
• your temperature goes below 36°C (96.8°F). 

Symptoms of an infection include:

• feeling shivery and shaking
• a sore throat
• a cough 
• breathlessness
• diarrhoea
• needing to pass urine (pee) a lot, or discomfort when you pass urine.

It is important to follow any specific advice your cancer treatment team gives you.

If you are having more than 1 course of treatment, you will have a blood test before the next cycle. If your white blood cell count is low, your doctor may delay your treatment for a short time, until your cell count increases.

This treatment can reduce the number of platelets in your blood. Platelets are cells that help the blood to clot.

If the number of platelets is low, you may bruise or bleed easily. You may have:

• nosebleeds
• bleeding gums
• heavy periods
• blood in your urine (pee) or stools (poo)
• tiny red or purple spots on the skin that may look like a rash.

Tell your doctor if you have any unexplained bruising or bleeding. You may need a drip to give you extra platelets. This is called a platelet transfusion.

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.

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.

This treatment may cause diarrhoea. Diarrhoea means passing more stools (poo) than is usual for you, or having watery or loose stools. If you have a stoma, it will be more active than usual.

If you have diarrhoea:

• try to drink at least 2 litres (3½ pints) of fluids each day
• avoid alcohol, caffeine, milk products, high-fat foods and high-fibre foods
• contact the hospital for advice.

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.

This treatment can affect your appetite. Don't worry if you do not eat much for a day or 2. But if your appetite does not come back after a few days, or if you are losing weight, tell your nurse or dietitian. They can give you advice. They may give you food or drink supplements. Or they may suggest changes to your diet or eating habits to help.

Some people get swelling: 

• around their eyes 
• in their hands, ankles or feet. 

This is because of a build-up of fluid. If you have any swelling, or if you put on weight very quickly, contact the hospital for advice. Your doctor may prescribe drugs called diuretics to make you pass more urine (pee). This helps get rid of some of the fluid. The swelling gets better after your treatment ends.

This treatment may affect your skin or cause sweating. You may have a rash, which may be itchy. Your doctor or nurse can tell you what to expect. If your skin feels dry, try using an unperfumed moisturising cream every day.

Always tell your doctor or nurse about any skin changes. They can give you advice and may prescribe creams or medicines to help. Any changes to your skin are usually temporary and improve when treatment finishes.

Rarely, a much more severe skin condition can develop. You may have a skin rash that then blisters, and your skin can peel. If this happens, contact the hospital straight away.

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.

You may get pain in your tummy (abdomen), or have indigestion. Your doctor can give you drugs to help improve these symptoms. Tell them if the pain gets worse or does not get better.

You may get pain in your muscles or joints for a few days after treatment. If this happens, tell your doctor so they can give you painkillers. Tell them if the pain does not get better. Having warm baths and taking regular rests may help.

This treatment can affect how your kidneys work. This is usually mild and goes back to normal after treatment finishes. You will have blood tests to check how well your kidneys are working. Tell your doctor or nurse if you have blood in your urine (pee) or you are passing urine less than usual.

It is important to drink at least 2 litres (3½ pints) of non-alcoholic fluid each day to help protect your kidneys.

This treatment may affect how your liver works. This is usually mild and goes back to normal after treatment. You will have blood tests to check how well your liver is working.

This treatment may cause headaches. If you have headaches, tell your doctor. They may give you painkillers to help.

Cladribine can cause problems sleeping, or sometimes sleepiness. It can also cause you to feel anxious. If you feel like this, tell your doctor.

It is important not to drive if you feel sleepy or drowsy.

This treatment can make you feel dizzy or unsteady. Let your doctor know if this happens. If you feel dizzy, do not drive.

This treatment may cause cancer cells to die and break down quickly. When cancer cells break down very quickly, it can cause a sudden release of large amounts of chemicals into the blood. This is called tumour lysis syndrome (TLS).

Your kidneys can usually keep these chemicals balanced. But they might not be able to cope with very large amounts. The chemical imbalance can affect how well your kidneys work and cause problems with your heart rhythm.

You will have regular blood tests to check the levels of these chemicals.

If you are at risk of TLS, your doctor can give you treatment to help prevent it. You may have:

• extra fluids through a drip
• medicines such as rasburicase or allopurinol.

Drinking at least 2 litres (3½ pints) of fluid a day will also help.

Your eyes may become watery and feel sore. Your doctor can prescribe eye drops to help with this. If your eyes become red and inflamed, tell your doctor. This is called conjunctivitis. You may need eye drops to treat it.

This treatment can cause changes to the lungs. Tell your doctor if you develop:

• a cough
• wheezing
• breathlessness.

You should also tell them if any existing breathing problems get worse. You may have tests to check your lungs.

After this treatment, any blood or platelet transfusions you have must always be treated with radiation (irradiated) first. This lowers the risk of the donated blood cells reacting against your own. It will not damage the blood or make you radioactive. 

Your doctor will record in your medical notes that you should only be given irradiated blood products. They will also give you a card to carry in case you are treated at another hospital. Keep this card with you at all times and remind your hospital team that you need irradiated blood or platelets.

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 (covid) 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 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.

Your doctor will advise you not to get pregnant or make someone pregnant while having this treatment. The drugs may harm a developing baby. It is important to use contraception during your treatment and for a while after treatment finishes. Your doctor, nurse or pharmacist can tell you more about this.

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.

Some cancer drugs can affect whether you can get pregnant or make someone pregnant. If you are worried about this, it is important to talk with your doctor before you start treatment.

If you have sex in the first few days after this treatment, you should use barrier protection such as a condom or dental dam. This will protect your partner if any of the drug is in your semen or vaginal fluids.

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.