Gliadel® wafers

Gliadel® wafers are small discs that contain the chemotherapy drug carmustine. They are sometimes used to treat a brain tumour called a glioma.

What are Gliadel wafers?

Gliadel® wafers are small discs that contain the chemotherapy drug carmustine. They are about the size of a 5 pence (5p) coin and may be used to treat a type of brain tumour called a glioma.

After the surgeon removes the brain tumour they insert the Gliadel wafers into the area where the tumour was.

It is best to read this information with our general information about chemotherapy and the type of brain tumour you have.

Your cancer team 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 Gliadel wafers are given

Gliadel wafers are not suitable for everyone. Your specialist brain surgeon (neurosurgeon) will explain to you if they are suitable for you. They may not know whether they can insert the wafers until you are having your operation.

During the operation the neurosurgeon places the Gliadel wafers into the area where the tumour was removed.

Usually, up to 8 wafers are used. The wafers release a chemotherapy drug called carmustine directly to the surrounding cancer cells. As they release the drug, the wafers dissolve over a period of 2-3 weeks. This means they do not need to be removed.

During your treatment, you will meet with someone from your cancer team, such as 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.

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.

Very common side effects

These side effects happen to 10 or more people in every 100 people (10% or more) who have this treatment.

The following side effects are in people who have been newly diagnosed with a high-grade glioma.

Possible effects on the nervous system

Gliadel wafers may have some effects on the nervous system. These side effects can also happen after surgery to the brain. Your specialist brain surgeon (neurosurgeon) and nurse will tell you what to expect after your operation

Seizures (fits)

You may be more likely to have seizures (fits). They are most likely to happen within the first 5 days after your operation. Your doctor may prescribe medicines for a short time to help prevent them. If you have been having seizures already, you can talk to your surgeon about the medicines you take.

Headaches and dizziness

Headaches and dizziness are common after brain surgery and with Gliadel treatment. Your doctor will tell you which painkillers will help. Tell them if the headaches or dizziness get worse. 

Temporary swelling in the brain

Gliadel wafers may cause swelling in the brain. This is usually temporary. It can also happen after surgery to the brain. Your doctor or nurse will usually give you steroids to help reduce swelling.

Tell your doctors or nurse straight away if you:

  • have severe headaches
  • feel weak in your arms or legs (on one or both sides)
  • have difficulty walking
  • feel confused, drowsy or sleepy
  • have difficulty speaking or changes in speech
  • feel sick (nauseas) or are sick (vomit).

If someone with you notices you have these symptoms, they should contact the hospital straight away.

An infection in the brain

Your doctors and nurses will be checking you closely for any signs of infection. Tell them if you have:

  • a temperature
  • flu-like symptoms
  • headaches
  • neck stiffness
  • sensitivity to bright light.

Mood changes

This treatment can cause changes in your mood. If you feel depressed or anxious, tell your cancer doctor, nurse or GP. They can help get you the support you need.

Slow wound healing

It may take longer for your wound to heal after your operation. This is because the Gliadel wafers can affect the healing process. Your doctor or nurse will check your wound regularly. If you notice any leaking from the wound, or swelling or redness in the area, tell your doctor or nurse straight away.

Feeling tired

Feeling tired is a common side effect of this treatment. 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.

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. 

Feeling sick

You may feel sick during this treatment, but this is usually mild. Your doctor, nurse or pharmacist may prescribe you anti-sickness drugs to help prevent or control sickness. Take the drugs exactly as they tell you to. 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.

Skin changes

Chemotherapy can affect your skin. It might feel dry. You may develop a rash, which may be itchy. Always tell your doctor, nurse or pharmacist about any skin changes. They can give you advice or prescribe creams or medicines to help.

If your skin feels dry, try using soap-free cleansers and unperfumed moisturising cream every day.

Hair loss

Some people may find they have some hair loss. Your nurse can talk to you about ways to cope with hair loss.

Your nurse can talk to you about ways to cope with hair loss. 

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.

Other side effects

These side effects happen to less than 10 in 100 people (less than 10%) who have this treatment. Some of them are much rarer than this but they are still important to know about. Rare means a side effect that happens to less than 1 in 1,000 people (less than 0.1%).

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.

Effects on the eyes

Your eyes may become watery and feel sore. Your doctor, nurse or pharmacist can give you advice and eye drops to help with this.

Contact the hospital on the 24-hour number if:

  • your eyes get red and inflamed (conjunctivitis)
  • you have pain in your eyes
  • you notice any change in your vision. 

Raised blood sugar levels

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

Signs of raised blood sugar include:

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

Tell your doctor or nurse if you have these symptoms. They can do tests to check your blood sugar level and give you advice.

If you already have diabetes, your blood sugars may be higher than usual. You may need to check them more often, or make changes to your diabetic treatment. Your diabetic doctor or nurse will talk to you about how to manage this.

Fluid build-up

This treatment can cause a build-up of fluid in the body. This will slowly get better after treatment ends. Contact the hospital on the 24-hour number if you:

  • are gaining weight 
  • have swelling in your face, legs or ankles.

They can give you advice and treatment to help.

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.

Low number of white blood cells

This treatment can reduce the number of white cells in your blood. These cells fight infection. If you have any signs of an infection, tell your doctor, nurse or pharmacist. These signs include:

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

Contact the hospital straight away on the 24-hour number if you have any of these symptoms:

  • a temperature above 37.5°C 
  • a temperature below 36°C
  • you feel unwell, even with a normal temperature.

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.

Urinary problems

Some people may have urinary infections or some urinary leakage (incontinence). If you think you have an infection or any other urinary symptoms contact the hospital straight on the 24-hour contact number you have been given.

Tummy pain and back pain

Tell your doctor, nurse or pharmacist if you have these symptoms.

Changes in thinking

Some people may feel extremely anxious, have abnormal thinking or see things that are not there (hallucinations). If you have any of these symptoms contact the hospital straight away on the 24-hour number.

Difficulty sleeping (insomnia)

If you are having trouble sleeping tell your doctor, nurse or pharmacist.

Other important information

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: 

Vaccinations

Cancer doctors usually recommend that people with cancer have vaccinations for flu and coronavirus (covid). They may also recommend other vaccines, such as Shingrix® for shingles. These all help reduce your risk of serious illness from these infections. Most people can have these vaccines, including people with weak immune systems.

You should not have live vaccines if your immune system is weak. This includes if you are having or recently had chemotherapy, radiotherapy or other cancer treatments that affect your immune system. Live vaccines can make you unwell because they contain a very weak version of the illness they protect you against. There are several live vaccines, including 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.

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.

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 in the first few days after treatment, your cancer team will usually advise using condoms or a dental dam to protect your partner.

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.

About our information

This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer.

Date reviewed

Reviewed: 01 October 2025
|
Next review: 01 October 2027
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

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