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Side effects of temozolomide (Temodal)

Find out about the side effects of the chemotherapy drug temozolomide.

Tell your doctor or nurse if you have any side effects so they can help you manage them. Your nurse will give you a contact number to ring if you have any questions or problems. If in doubt, call them.

Contact your doctor or nurse immediately if any of your side effects get severe or if you have signs of infection, including a temperature above 37.5C.

The side effects may be different if you are having temozolomide with other cancer treatments.

Common side effects

Each of these effects happens in more than 1 in 10 people (10%). You might have one or more of them.

You might feel very tired during your treatment. It might take 6 months to a year for your energy levels to get back to normal after the treatment ends. A low red blood cell count will also make you feel tired.

You can do things to help yourself, including some gentle exercise. It’s important not to push yourself too hard. Try to eat a well balanced diet.

Talk to your doctor or nurse if you are finding the tiredness difficult to manage.

Your hair may get thinner. It usually begins falling out gradually within 2 to 3 weeks after treatment starts.

Your hair grows back once your chemotherapy treatment has finished. This can take several months and your hair is likely to be softer.

Tips

  • Use gentle hair products such as baby shampoos.
  • Don't use perms or hair colours on thinning hair.
  • Use a soft baby brush and comb thinning hair gently.
  • Pat your hair dry gently rather than rubbing.

Feeling or being sick can be severe. It can start a few hours after treatment and last for a few days. Anti sickness injections and tablets can control it. Tell your doctor or nurse if you feel sick. You may need to try different anti sickness medicines to find one that works.

Contact your doctor or nurse straight away if you’ve been sick more than once in a day.

Tips

  • Avoid eating or preparing food when you feel sick.
  • Avoid fried foods, fatty foods or foods with a strong smell.
  • Drink plenty of liquid to stop you from getting dehydrated.
  • Relaxation techniques help control sickness for some people.
  • Ginger can help – try it as crystallised stem ginger, ginger tea or ginger ale.
  • Fizzy drinks help some people when they are feeling sick.

You might lose your appetite for various reasons when you are having cancer treatment. Sickness, taste changes or tiredness can all put you off food and drinks.

Tips

  • Eating several small meals and snacks throughout the day can be easier to manage.
  • Ask your doctor or nurse to recommend high calorie drinks to sip between treatments, if you are worried about losing weight.
  • You can make up calories between treatments for the days when you really don’t feel like eating.
  • Drink plenty of fluids even if you can't eat.
  • Don't fill your stomach with a large amount of liquid before eating.
  • Try to eat high calorie foods to keep your weight up.

You might have an itchy rash and dry skin.

Let your doctor or nurse know if you have headaches. They can give you painkillers such as paracetamol to help.

Constipation is easier to sort out if you treat it early. Drink plenty of fluids and eat as much fresh fruit and vegetables as you can. Try to take gentle exercise, such as walking.

Tell your doctor or nurse if you are constipated for more than 3 days. They can prescribe a laxative.

Women might stop having periods (amenorrhoea) but this may be temporary.

Occasional side effects

Each of these effects happens in more than 1 in 100 people (1%). You might have one or more of them.

Signs of an infection include headaches, aching muscles, a cough, a sore throat, pain passing urine, or feeling cold and shivery.

Contact your advice line or doctor straight away if you have any of these signs, or your temperature goes above 37.5C or below 36C. Severe infections can be life threatening.

Chemotherapy reduces the number of white blood cells in the blood. This increases your risk of infections. White blood cells help fight infections.

When the level is very low it is called neutropenia (pronounced new-troh-pee-nee-ah).

You have antibiotics if you develop an infection. You might have them as tablets or as injections into the bloodstream (intravenously). To have them into your bloodstream you need to go into hospital.

Chemotherapy makes the level of red blood cells fall (anaemia). Red blood cells contain haemoglobin, which carries oxygen around the body. When the level of red blood cells is low you have less oxygen going to your cells. This can make you breathless and look pale. Tell your doctor or nurse if you feel breathless.

You have regular blood tests to check your red blood cell levels. You might need a blood transfusion if the level is very low. After a transfusion, you will be less breathless and less pale.

You can also feel tired and depressed when your blood count is low and feel better once it is back to normal. The levels can rise and fall during your treatment. So it can feel like you are on an emotional and physical roller coaster.

You might notice you:

  • bruise more easily
  • have nosebleeds
  • have bleeding gums when you brush your teeth

This is due to a drop in the number of platelets that help clot your blood.

If your platelets get very low you may have lots of tiny red spots or bruises on your arms or legs called petechiae.

Tell your doctor or nurse straight away if you have petechiae.

You have a platelet transfusion if your platelet count is very low. It is a drip of a clear fluid containing platelets. It takes about 15 to 30 minutes. The new platelets start to work right away. 

Blood clots can develop in the deep veins of your body. This is called deep vein thrombosis (DVT).

A DVT usually develops in the thigh or lower leg. A clot can block the normal flow of blood through the veins.

A blood clot can be very serious if it starts to move through your body. It can cause a blockage in your heart or lungs, although this isn’t common.

Treatment is with drugs to thin the blood.

Tell your doctor immediately if you have:

  • pain and swelling in one of your legs, usually at the back of your leg below the knee
  • warm, red skin in the affected area
  • shortness of breath
  • chest pain, which may be worse when breathing in

Tell your nurse or doctor if you have heartburn or acid reflux. They can give you anti acid medicine.

Sleeping upright in bed helps to prevent heartburn. You can use pillows or cushions to support yourself.

Let your doctor or nurse know straight away if you have any problems swallowing.

Swelling of hands and feet is due to fluid build up. This is called oedema. Let your doctor or nurse know if you have any swelling.

This drug can cause lung problems.

Let your doctor or nurse know straight away if you suddenly become breathless or develop a cough.

Do not drive or operate machinery if you have this symptom and speak to your doctor. 

You might have some hearing loss, especially with high pitched sounds. Tell your doctor or nurse if you notice any changes.

Your mouth might get very dry, which can be uncomfortable. Various things can help.

Tips

  • Try to drink at least 3 pints (one and a half litres) of fluid a day.
  • Choose meals that are moist.
  • Use gravies and sauces to make swallowing easier.
  • Take regular sips of water with your meal to help you chew and swallow your food.
  • Suck small amounts of ice chips to refresh your mouth.
  • Chew sugar free chewing gum.
  • Try eating fresh pineapple.
  • Get your doctor or nurse to give you medicines to stimulate your salivary glands.
  • Ask your doctor about artificial saliva products, such as tablets, mouthwashes, gum, pastilles, and toothpaste.
  • It is very important to have regular check ups with your dentist.

Let your doctor or nurse know if you have pain in your joints during or after having treatment. There are lots of ways to treat pain, including relaxation and painkillers.

You may feel drowsy with this treatment. Do not operate machinery or drive if you are feeling drowsy.

This usually happens with the first or second treatment. Symptoms include a skin rash, itching, feeling hot and shivering. Other symptoms include redness of the face, dizziness, a headache, shortness of breath and anxiety.

You might not feel like eating and may lose weight. It is important to eat as much as you can.

Tips

  • Eating several small meals and snacks throughout the day can be easier to manage.
  • Ask your doctor to recommend high calorie drinks to sip between treatments if you are worried about losing weight.
  • Eat whatever you feel like eating rather than what you think you should eat.
  • Make up calories between treatments for the days when you really don’t feel like eating.
  • Drink plenty of fluids even if you can't eat.
  • Don't fill your stomach with a large amount of liquid before eating.
  • Try to eat high calorie foods to keep your weight up.
Talk to your dietitian about having high calorie drinks to boost your calorie intake if you need them.

You may feel:  

  • as if you want to pass urine all the time (but when you go, there isn't much there)
  • as if you have a bladder infection (cystitis)
  • a burning pain when you do pass urine

Try to drink plenty of water. Many people think that drinking cranberry juice can be helpful with bladder problems. But cranberry juice can increase the effects of warfarin (a blood thinner or anticoagulant). You should not drink cranberry juice if you are taking warfarin. 

Your bladder inflammation should settle down after the treatment is over.  

Tell your doctor if you have any pain when passing urine. It could be a sign that you have an infection. You may need antibiotic treatment.

You might feel like you are shaking or have tremors. 

Tell your doctor if you have any fits, twitching or jerking of your limbs. 

You might have some muscle weakness or back pain. Let your doctor or nurse know, painkillers or gentle exercise might help.

Don’t drive or operate machinery if you have this.

Changes in taste can make you go off certain foods. Many people go off tea and coffee, for example. You might also find that some foods taste different. Some people find that they prefer to eat spicier foods.

Your taste usually gradually goes back to normal when your treatment is over. It may take a few weeks.

Tips

  • Choose foods that have strong flavours, such as herbs, spices, marinades and sauces if all your food tastes the same.
  • Season your food with spices or herbs, such as rosemary, basil and mint.
  • Garnish cold meat or cheese with pickle or chutney.
  • Try lemon or green tea if tea or coffee taste strange.
  • Sharp tasting fizzy drinks such as lemonade or ginger beer are refreshing.
  • Some people find that cold foods taste better than hot foods.

You might feel depressed or sleep more whilst having this treatment. You can also feel more worried or panicky than usual. This is common so don’t be embarrassed to talk to your doctor or nurse. They can find the best person to help you.

Tell your doctor or nurse if you have this.

You have regular blood and urine tests to check this. If you have diabetes you may need to check your blood sugar levels more often than usual. 

Tell your doctor or nurse if you have diarrhoea. They can prescribe medicine to help you. 

Drink at least 2.5 litres of fluid a day. This helps to keep you hydrated.

Ask your nurse about soothing creams to apply around your back passage (rectum). The skin in that area can get very sore and even break if you have severe diarrhoea.

Contact your doctor or nurse immediately if you have diarrhoea 4 or more times a day, or any diarrhoea at night.

The changes are usually very mild and unlikely to cause symptoms. They will almost certainly go back to normal when treatment is finished. 

You have regular blood tests throughout your treatment so your doctor can check this.

Talk to your doctor or nurse if you’re having problems sleeping. It can help to change a few things about when and where you sleep.

Tips

  • Go to bed and get up at the same time each day.
  • Make sure the temperature is right.
  • Spend time relaxing before you go to bed - have a bath, read or listen to music.
  • Do some light exercise each day to help tire yourself out.
  • Avoid caffeine (coffee, tea, chocolate and cola drinks) after early afternoon.
  • Have a light snack before you go to bed to stop hunger waking you up.

Other occasional side effects include:

  • difficulty speaking
  • difficulty balancing
  • forgetfulness and difficulty concentrating
  • tingling sensations in the skin

Rare side effects

Each of these effects happens in fewer than 1 in 100 people (1%). You might have one or more of them.

There is a small risk that you may get a second cancer some years after this treatment. Your doctor will discuss this with you.

If you get a high temperature, let your treatment team know straight away. Ask them if you can take paracetamol to help lower your temperature.

You may gain weight while having this treatment. You may be able to control it with diet and exercise. Tell your doctor or nurse if you are finding it difficult to control your weight. 

This treatment might cause mood changes. Speak to your doctor or nurse if you have this. They can give you advice. 

You might notice a ringing sound in your ears (tinnitus). This often gets better on its own once the treatment ends.

This makes you feel as though your heart is racing. Your doctor might ask you to have tests to check your heart such as an electrocardiogram (ECG). 

Don’t use sunbeds or sit in the sun. Cover up or use a sun block if you go out in the sun. Remember to put sun cream on your head or wear a hat if you have lost any hair there.

Tell your doctor or nurse if you have headaches, nose bleeds, blurred or double vision or shortness of breath. Your nurse will check your blood pressure regularly.

You may have difficulty passing urine or you may need to go more urgently. Let your doctor or nurse know if you have this. 

Swollen veins near your anus (called piles or haemorrhoids) can be painful when you open your bowels. You can try a cream from your pharmacist or tell your doctor. 

Let your doctor or nurse know if you are sweating much more than normal.

Tips

  • Cut out coffee, tea and nicotine.
  • Cut down on alcohol.
  • Sip cold or iced drinks.
  • Wear layers of light clothing so you can take clothes off if you overheat.
  • Have layers of bedclothes to remove as you need to.
  • Wear natural fibres such as silk or cotton instead of man made fabrics.

You might have a blood clot in your lung.

Let your nurse or doctor know straight away if you have a sudden cough, breathlessness or chest pain

You might find you have difficulty controlling your bowels (incontinence).

This can be upsetting. Talk to your doctor or nurse about what they can do to help.

You might find things have a different smell on treatment.  Foods might smell differently.

This often goes back to normal once your treatment has finished.

Seeing or hearing things that are not there (hallucinations) can occur with this treatment. Speak to your doctor if this happens to you. 

Other rare side effects include:

  • red spots under the skin
  • dry or sore eyes
  • a blocked nose due to inflamed sinuses

About temozolomide

More information about this treatment

We haven't listed all the very rare side effects of this treatment. For further information see the electronic Medicines Compendium (eMC) website.

You can report any side effect you have that isn’t listed here to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.

Information and help

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