Temozolomide (Temodal) | Cancer Research UK
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What temozolomide is

Temozolomide is a chemotherapy drug used to treat certain types of brain tumours called glioblastoma multiforme or anaplastic astrocytoma.

For newly diagnosed glioblastoma multiforme temozolomide is first used together with radiotherapy and then as a treatment on its own.

It is used as a treatment on its own for glioblastoma multiforme or anaplastic astrocytoma that has come back or where previous treatment did not work. 


How temozolomide works

Temozolomide is a type of drug known as an alkylating agent and works by stopping cancer cells from making new DNA. DNA stands for DeoxyriboNucleic Acid. It is the genetic material of a cell. If cancer cells can't make DNA, they can’t split into 2 new cells, so the cancer can't grow.


How you have temozolomide

You take temozolomide as capsules that you swallow whole with a glass of water. Take them on an empty stomach – for example, 1 hour before or after meals. Store the capsules in a safe place away from children.

If you are having temozolomide alongside radiotherapy, you have radiotherapy for 6 to 7 weeks. You take the temozolomide capsules each day during this time. It is best to take them at the same time each day. If you have temozolomide together with radiotherapy you are at higher risk of getting a type of lung infection called pneumocystis carinii pneumonia, so your doctor will prescribe medicines to help protect you against this. 

After the radiotherapy, or if you have a brain tumour that has come back, you may have temozolomide as a course of cycles of treatment. You take the temozolomide capsules for 5 days every 4 weeks. You may repeat this treatment up to 6 times.

It is very important that you take capsules according to the instructions your doctor or pharmacist gave you. You should take the right dose, not more or less. And never stop taking a cancer drug without talking to your specialist first. 

If you accidentally take more temozolomide capsules than you were told to, contact your doctor, pharmacist or nurse straight away. 

If you forget to take a dose of temozolomide take the missed dose as soon as possible during the same day. If more than a full day has gone by, check with your doctor. Don't take a double dose to make up for a forgotten dose, unless your doctor tells you to do that.


Tests during treatment

You have blood tests before starting treatment and regularly during your treatment. The tests check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.


About side effects

We've listed the side effects associated with temozolomide 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.

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 temozolomide with other drugs or alongside radiotherapy.

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


Common side effects

More than 10 in every 100 people have one or more of the side effects listed below.

  • Tiredness and weakness (fatigue) during and after treatment – most people find their energy levels are back to normal within 6 months to a year
  • Hair loss – you may have some thinning within a month of starting treatment. Your hair will grow back when the treatment is over
  • Feeling or being sick can start within a couple of hours of having the capsules and may last until the next day – take anti sickness medicines regularly and tell your doctor or nurse if they aren't working
  • Loss of appetite
  • An itchy rash and dry skin
  • Headaches
  • Constipation – drink plenty of fluids and tell your doctor or nurse if it doesn't get better within a few days
  • Women may stop having periods (amenorrhoea) but this may only be temporary
  • Loss of fertility may happen with this drug – you may not be able to get pregnant or father a child after treatment so talk to your doctor before starting treatment if you plan to have a baby in the future. It may be possible for men to store sperm beforehand

Occasional side effects

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

  • Dizziness
  • 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
  • Tiredness and breathlessness due to a drop in red blood cells (anaemia) – you may need a blood transfusion
  • Bruising more easily due to a drop in platelets – you may have nosebleeds, or bleeding gums after brushing your teeth. Or you may have lots of tiny red spots or bruises on your arms or legs (known as petechiae)
  • Taste changes
  • Anxiety
  • Difficulty sleeping
  • Liver changes – you will have regular blood tests to check how well your liver is working
  • A higher risk of blood clots – let your doctor or nurse know if you have any leg pain, redness or swelling that feels warm to the touch
  • Muscle weakness or back pain
  • Weight loss
  • Diarrhoea – drink plenty of fluids and tell your doctor or nurse if it doesn't get better within a few days
  • Tummy (abdominal) pain and an upset stomach
  • Higher levels of sugar in the blood – tell your nurse or doctor if you feel very thirsty and pass a lot of urine
  • Confusion or drowsiness – let your doctor or nurse know if you have this
  • Feeling sad or depressed – let your doctor or nurse know if you have this
  • Difficulty speaking
  • Difficulty balancing
  • Fits (seizures)
  • Forgetfulness and difficulty concentrating
  • Tingling sensations in the skin
  • Shaking (tremor)
  • Blurred vision or other eyesight changes
  • Loss of hearing
  • Lung changes causing breathlessness or a cough
  • Fluid build up causing swollen legs or hands
  • Heartburn
  • Difficulty swallowing
  • A dry mouth
  • Swollen, painful joints
  • Needing to pass urine often and discomfort when passing urine – let your nurse or doctor know if you have this
  • An allergic reaction – let your nurse or doctor know straight away if you have a sudden skin rash, itching, breathlessness or swelling of the lips, face or throat

Rare side effects

Fewer than 1 in 100 people have these effects.

  • A second cancer or leukaemia some years after treatment.
  • A high temperature (fever) and chills – this does not usually last for long
  • Red spots under the skin
  • Weight gain
  • Mood swings
  • Hallucinations (seeing or hearing things that are not there)
  • Dry or sore eyes
  • Ringing in the ears (tinnitus)
  • A feeling of your heart beating fast (palpitations)
  • Blood clots in the lung – let your nurse of doctor know straight away if you have a sudden cough, breathlessness or chest pain
  • Sensitivity of the skin to sunlight – cover up with clothing and use sunscreen if you need to go out into the sun
  • Higher blood pressure – your nurse will check your blood pressure regularly
  • A blocked nose due to inflamed sinuses
  • Difficulty in controlling bowel movements
  • Difficulty passing urine
  • Piles (haemorrhoids) – let your doctor or nurse know if you have this
  • Increased sweating
  • Changed sense of smell

Important points to remember

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 and for at  least 6 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 chemotherapy

You should not have immunisations with live vaccines while you are having chemotherapy 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 chemotherapy. 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 temozolomide

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 www.medicines.org.uk.

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 www.mhra.gov.uk.

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Updated: 29 April 2015