Temozolomide

Temozolomide is a chemotherapy drug. It is used to treat certain types of brain tumour, such as gliomas and anaplastic astrocytomas. It may also be used to treat other cancers.

What is temozolomide?

Temozolomide is used to treat certain types of brain tumour such as glioma and anaplastic astrocytoma. It may sometimes be used to treat other cancers. It is best to read this information 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.

More information about this treatment

This information is correct at time of publishing. But sometimes the types of cancer this treatment is used for, or treatment side effects, may change between revision dates.

You can talk to your cancer team if you want more detailed information about this treatment. Or visit the electronic Medicines Compendium (eMC) website, which has patient information leaflets (PIL) for individual drugs.

How temozolomide is given

During a course of treatment, you usually see a:

  • cancer doctor
  • chemotherapy nurse or specialist nurse
  • specialist pharmacist.

This is who we mean when we mention doctor, nurse or pharmacist in this information.

You will have regular blood tests while you are taking temozolomide. This is to check that it is safe for you to keeping taking chemotherapy.

You will speak to a doctor, nurse or pharmacist regularly during your treatment. They will talk to you about your blood results and ask how you have been feeling.

Your course of chemotherapy

Temozolomide comes in capsules, so you can take it at home. Temozolomide may be given on its own, or with other cancer treatments.

Chemotherapy is usually given as a course of several cycles of treatment over a few months. Your doctor, nurse or pharmacist will discuss your treatment plan with you. They may give you a copy of the treatment plan to take home.

The doctor, nurse or pharmacist will give you the capsules to take home. You may be given capsules of different strengths. They may also give you anti-sickness drugs and other medicines to take home. Always take them exactly as explained. This is important to make sure they work as well as possible for you.

Taking temozolomide capsules

You should not have anything to eat 1 hour before, or 1 hour after, taking the capsules. They must be swallowed whole with a glass of water. The capsules should not be chewed, opened or crushed. Take them at the same time every day.

If you forget to take the capsules, you should take the missed dose as soon as possible within the same day. If a full day has gone by, let your doctor or nurse know. Do not take a double dose unless they tell you to.

Other things to remember about your capsules:

  • Wash your hands after taking your capsules.
  • Other people should avoid direct contact with the chemotherapy drugs.
  • Keep them in the original package and at room temperature, away from moisture, heat and direct sunlight.
  • Keep them safe, somewhere children cannot see or reach them.
  • If you are sick just after taking the capsules, contact the hospital. Do not take another dose.
  • If your treatment is stopped, return any unused capsules/tablets to the pharmacist.

About side effects

We explain the most common side effects of this treatment here. We also include some that are less common. 

You may get some of the side effects we mention, but you are unlikely to get all of them. And you may have some side effects, including rarer ones, that we have not listed here. 

Other cancer treatments may cause different side effects. If you are also having other cancer treatment, you may have other side effects.

Always tell your doctor, nurse or pharmacist about any side effects you have. They can give you: 

  • drugs to help control some side effects 
  • advice about managing side effects. 

It is important to take any drugs exactly as explained. This means they will be more likely to work for you.

Serious and life-threatening side effects

Some cancer treatments can cause serious side effects. Sometimes, these may be life-threatening. Your doctor, nurse or pharmacist can explain the risk of these side effects to you.

Contact the hospital

Your doctor, nurse or pharmacist will give you 24-hour contact numbers for the hospital. If you feel unwell or need advice, you can call at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.

Common side effects

Risk of infection

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

An infection can be very serious when the number of white blood cells is low. Your doctor may give you antibiotics and other drugs to take during this treatment. These may help reduce your risk of getting an infection. 

But it is still important to get any infection treated as soon as possible. If you have any of the following symptoms, contact the hospital straight away on the 24-hour number:

  • a temperature above 37.5°C 
  • a temperature below 36°C
  • you feel unwell, even with a normal temperature
  • you have symptoms of an infection.

Symptoms of an infection include:

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

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

Your white blood cell count will usually return to normal before your next treatment. You will have a blood test before having more treatment. If your white blood cell count is low, your doctor may delay your treatment for a short time, until your cell count increases.

You may be given a drug called G-CSF. This encourages the body to make more white blood cells. You have it as a small injection under the skin.

Bruising and bleeding

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, brown or purple spots that may look like a rash – these spots can be harder to see if you have black or brown skin. 

If you have any unexplained bruising or bleeding, contact the hospital straight away on the 24-hour number. You may need a drip to give you extra platelets. This is called a platelet transfusion.

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 feel:

  • very low in energy
  • breathless 
  • dizzy and light-headed. 

If you have these symptoms, contact the hospital straight away on the 24-hour number. You may need treatment for anaemia. If you are very anaemic, you may need a drip to give you extra red blood cells. This is called a blood transfusion.

Feeling sick

Your doctor, nurse or pharmacist will prescribe anti-sickness drugs to help prevent or control sickness. Take the drugs exactly as they tell you to, even if you do not feel sick. It is easier to prevent sickness than to treat it after it has started.

If you feel sick, take small sips of fluid often and eat small amounts regularly. It is important to drink enough fluids. If you continue to feel sick, or if you are sick (vomit) 1 to 2 times in 24 hours, contact the hospital on the 24-hour number as soon as possible. They will give you advice. They may change your anti-sickness treatment. Let them know if you still feel sick.

Constipation

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 on the 24-hour number for advice. They can give you drugs called laxatives to help. 

If you have not been able to pass stools for over 2 days and are being sick, contact the 24-hour number straight away. 

Diarrhoea

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

If you are passing loose stools 3 or more times a day and this is not normal for you, contact the hospital as soon as possible on the 24-hour number. Follow the advice they give you about:

  • taking anti-diarrhoea medicines 
  • drinking enough fluids to keep you hydrated and to replace lost salts and minerals
  • any changes to your diet that might help. 

They might also ask you for a specimen of your stool to check for infection.

Loss of appetite

This treatment can affect your appetite. Don’t worry if you do not eat much for 1 or 2 days. But if your appetite does not come back after a few days, or if you are losing weight, tell your doctor, nurse or pharmacist. 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.

Sore mouth and throat

This treatment may cause a sore mouth and throat. You may also get mouth ulcers. This can make you more likely to get a mouth or throat infection. Use a soft toothbrush to clean your teeth or dentures in the morning, at night and after meals.

Contact the hospital straight away on the 24-hour number, if:

  • a sore mouth or throat affects how much you can drink or eat 
  • your mouth, tongue, throat or lips have any blisters, ulcers or white patches. 

They can give you advice, and mouthwash or medicines to help with the pain or to treat any infection. Follow their advice and make sure you:

  • drink plenty of fluids
  • avoid alcohol and tobacco
  • avoid food or drinks that irritate your mouth and throat.

Feeling tired

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 ends. Try to pace yourself and plan your day so you have time to rest. Gentle exercise, like short walks, can help you feel less tired. 

If you feel sleepy, do not drive or use machinery.

Headaches and seizures

This treatment may cause headaches. If you have a headache, tell your doctor or nurse. They can give you painkillers to help.

This treatment can cause seizures (fits). If you notice any of these symptoms, tell your doctor or nurse straight away. They may make some changes to your treatment.

If you notice these effects, it is important not to drive or operate machinery.

Hair loss

Your hair will get thinner. Or you may lose all the hair from your head. You may also lose your eyelashes and eyebrows, as well as other body hair. Hair loss usually starts after your first or second treatment.

If you want to cover up hair loss, there are different ways you can do this. Your nurse will give you information about coping with hair loss

Remember to protect your skin from the sun. Use suncream with a sun protection factor (SPF) of at least 30 on your scalp. Or cover up with a hat or scarf.

Hair loss is almost always temporary. Your hair will usually grow back after treatment ends.

Skin changes

This treatment may affect your skin. It can cause a rash, which may be itchy. If you have had radiotherapy recently or in the past, the area that was treated may become red or sore. Your doctor or nurse can tell you what to expect. If your skin feels dry, try using an unperfumed moisturising cream every day.

Your skin may be more sensitive to the sun and may burn more easily during treatment and for several months after. If you are out in the sun, use a suncream with a high sun protection factor (at least SPF 30) to protect your skin. Cover up with clothing and wear a hat.

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 serious skin condition can develop. You may have:

  • a skin rash which then blisters
  • peeling skin
  • flu-like symptoms, such as a high temperature and joint pain.

If you have any of these symptoms, contact your doctor or hospital straight away.

Effects on the nervous system

Temozolamide may affect the nervous system. You may have:

  • problems with balance and co-ordination
  • tingling, numbness or a burning feeling in your arms, hands, legs, feet or face
  • difficulty concentrating
  • difficulty remembering things
  • problems speaking.

Tell your doctor straight away if you notice any of these effects.

Hepatitis B reactivation

If you have had Hepatitis B (a liver infection) in the past, this treatment can make it active again. Your doctor or nurse will talk to you about this and may test you for Hepatitis B before, during, and after treatment.

Less common side effects

Allergic reaction

  • a skin rash or itching
  • feeling breathless or wheezy
  • swelling of your face, mouth or throat.

If you feel unwell or have any of these signs, contact the hospital straight away on the 24-hour number. Do not take any more of this treatment until you have checked with them.

Always call 999 if swelling happens suddenly or you are struggling to breathe.

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.

Muscle or joint pain

You may get pain in your muscles or joints. If this happens, tell your doctor or nurse. They can give you advice and painkillers or other drugs to help. Being physically active and keeping to a healthy weight may help with the pain. It can keep your joints flexible and reduce stress on them. If the pain does not get better, tell your doctor or nurse. They may talk to you about changing to a different hormonal drug.

Fluid build-up

You may gain weight, or your face, ankles and legs may swell. This improves slowly after your treatment has finished. Tell your doctor, nurse or pharmacist if you notice this side effect.

Raised blood sugar levels

This treatment may raise your blood sugar levels and increase the risk of diabetes. 

You will have regular blood tests to check this. 

Signs of raised blood sugar include:

  • feeling thirsty
  • needing to pass urine (pee) more often than usual
  • feeling more tired than usual.

Contact the hospital on the 24-hour number if you have these symptoms during treatment or after it ends.

If you already have diabetes, your blood sugar levels may be higher than usual. You may need advice and support from your GP or diabetes team about managing this.

Effects on the lungs

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

  • a cough that does not go away
  • wheezing
  • breathlessness.

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

Hearing changes

This treatment may cause hearing changes, including hearing loss. You may have ringing in the ears. This is called tinnitus. You may also become unable to hear some high-pitched sounds. Hearing changes may get better after this treatment ends. But this does not always happen. If you notice any changes in your hearing, tell your doctor, nurse or pharmacist.

Eyesight changes

This treatment can affect your eyes and eyesight. If you have sore eyes or notice changes to your vision, contact your doctor straight away.

Changes to your taste

Some foods may taste different or have no taste. Try different foods to find out what tastes best to you. You may also get a bitter or metallic taste in your mouth. Your doctor, nurse or pharmacist can give you advice. It might help to try:

  • sucking sugar-free sour or boiled sweets
  • eating cold foods
  • eating sharp-tasting fresh fruit.

Taste changes usually get better after treatment ends. We have more information about coping with changes to taste.

Mood changes

You may feel low or depressed, or have mood swings, during this treatment. Talking to family and friends about how you feel might help. If mood changes last for more than a few weeks, tell your doctor, nurse or pharmacist. They can talk to you about different ways to manage low mood or depression.

Second cancer

This treatment can increase the risk of developing a second cancer years later. This is rare. The benefits of treatment usually far outweigh this risk. Your doctor can talk to you about this.

Other information

Blood clot risk

Cancer and some cancer treatments can increase the risk of a blood clot. Contact the hospital straight away on the 24-hour number if you have any of these symptoms during or after treatment:

  • throbbing pain or swelling in a leg or arm
  • reddening of the skin in the area – if you have black or brown skin, this can be harder to notice, but the skin might become darker
  • suddenly feeling breathless or coughing.

Always call 999 if you have:

  • chest pain
  • difficulty breathing.

A blood clot is serious, but it can be treated with drugs called anticoagulants. These thin the blood. Your doctor, nurse or pharmacist can give you more information about preventing and treating blood clots.

Vaccinations

Doctors usually recommend that people with cancer have vaccinations for flu and for coronavirus (covid). These help reduce your risk of serious illness from these infections. Most people can have these vaccines, including people with weak immune systems.

If your immune system is weak, you should not have live vaccinations. Live vaccines can make you unwell because they contain a very weak version of the illness they will protect you against. Live vaccines include Zostavax®, which is a shingles vaccine, and the yellow fever vaccine.

It is important to ask your doctor, nurse or pharmacist for advice about having vaccinations. They can explain what vaccines are right for you and when it is best to have them.

Fertility

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.

Sex

It is possible that small amounts of chemotherapy may be passed on through vaginal fluids or semen. If you have sex during this treatment, your cancer team will usually advise using condoms or a dental dam to protect your partner.

Contraception

Your doctor, nurse or pharmacist will advise you not to get pregnant or make someone pregnant while having this treatment and for some time afterwards. The drugs may harm a developing baby. It is important to use contraception to prevent pregnancy. Follow their advice about:

  • what types of contraception to use 
  • how long after treatment you should continue to use contraception. 

Breastfeeding

You are advised not to breastfeed while having this treatment, or for some time after treatment ends. This is because the drugs could be passed to the baby through breast milk. 

Your doctor, nurse or pharmacist can give you more information.

Medical and dental treatment

If you need medical treatment for any reason other than cancer, always tell the healthcare professional that you are having cancer treatment. Give them the contact details for your cancer doctor or cancer team so they can ask for advice.

If you have appointments with a dentist, always tell them you are having cancer treatment. Talk to your cancer team before you have any dental treatment.

Other medicines

Some medicines can affect how this treatment works or be harmful while you are having it. Always tell your cancer doctor, nurse or pharmacist about any drugs you are taking or planning to take, such as: 

Lactose

This treatment contains lactose. If you have an intolerance to some sugars, talk to your doctor before you start this treatment.

About our information

  • Reviewers

    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.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

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We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

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Date reviewed

Reviewed: 01 November 2023
|
Next review: 01 November 2025
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.