What is thalidomide?

Thalidomide is a targeted therapy drug. It is used to treat myeloma. It may sometimes be used to treat other cancers. It is best to read this information with our general information about the type of cancer you have.

Thalidomide is both a targeted therapy drug and an immunotherapy drug. It works in several different ways.

Thalidomide can:

  • help the immune system attack and destroy cancer cells (immune system modulator)
  • kill or stop the growth of cancer cells (cancer growth inhibitor)
  • block the development of new blood vessels which cancer cells need to grow and spread (angiogenesis inhibitor).

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

How is thalidomide given?

You will be given thalidomide as an outpatient. During treatment you usually see a cancer doctor, a cancer nurse or specialist nurse, and a specialist pharmacist. This is who we mean when we mention doctor, nurse or pharmacist in this information.

You will have regular blood tests during treatment to check your blood cell levels and how well your liver is working.

Your course of treatment

Thalidomide comes in capsules, so you can take it at home. Thalidomide is usually taken with other chemotherapy drugs and steroids as treatment for myeloma. Your doctor will decide which combination of drugs you have. Sometimes you may have thalidomide on its own or with just a steroid.

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

Taking thalidomide

You take thalidomide once a day. It can make you feel sleepy, so it is best to take it in the evening before you go to bed. Swallow them whole with a glass of water. The capsules should not be chewed or opened. Take them at the same time every day.

Always take your capsules as directed by your doctor, nurse or pharmacist. This is to make sure they work as well as possible for you.

If you forget to take your thalidomide and less than 12 hours have passed, you should take the dose as soon as possible. If more than 12 hours have passed, do not take the missed dose. Just take your usual dose at the usual time the next day. Do not take a double dose unless your doctor tells you to.

There are some important things to remember when taking your capsules:

  • Keep them in the original packaging.
  • Keep them safe and out of sight and reach of children.
  • If you are sick just after taking the capsules, contact the hospital. Do not take another dose without talking to your doctor first.
  • If your treatment is stopped, return any remaining capsules to the pharmacist. Do not flush them down the toilet or throw them away.
  • Thalidomide can make you feel sleepy. Because of this, you should not drink alcohol while taking thalidomide.
  • If you plan to travel abroad, check whether the country you are visiting has any special rules about thalidomide.

Preventing pregnancy while taking thalidomide

You must not get pregnant or make someone pregnant while having thalidomide and for a while after treatment finishes. This is because thalidomide can cause birth defects in developing babies.

You will have to take part in a pregnancy prevention programme while taking thalidomide. Even if you do not think you are at risk of getting pregnant or making someone pregnant, you may still be included in this programme. You can talk to your doctor or specialist nurse about this.

The pregnancy prevention programme involves:

  • Being given written information about the risks of thalidomide
  • Being given advice about contraception – you may be advised to use different contraception during your treatment
  • Having pregnancy tests (if it is possible you could become pregnant).

Your doctor or specialist nurse will ask you to sign a consent form once you have read the information.

If during treatment, you think you might be pregnant or have made someone pregnant, contact your doctor or specialist nurse straight away.

About side effects

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.

Serious and life-threatening side effects

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.

Contact the hospital

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.

More information

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.

Common side effects of thalidomide

Risk of infection

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.

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.

You will have regular blood tests during treatment. If needed, your doctor may reduce or delay your treatment for a short time, until your cell count increases.

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 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.

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 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.

Feeling tired

Thalidomide can make you feel tired. Taking your thalidomide in the evening or before you go to bed can help with this. You may find that you feel less tired as you continue to take the drug. Tell your doctor if this continues to be a problem for you. 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 operate machinery.

Dizziness, blurred vision, drowsiness

This treatment can cause dizziness, blurred vision or drowsiness. Do not drive or operate machinery if you have these side effects. Talk to your doctor or nurse if you notice any of these effects.

Numb or tingling hands or feet (peripheral neuropathy)

This treatment affects the nerves, which can cause numb, tingling or painful hands or feet. You may find it hard to fasten buttons or do other fiddly tasks.

Tell your doctor if you have these symptoms. They sometimes need to lower the dose of the drug. The symptoms usually improve slowly after treatment finishes, but for some people they may never go away. Talk to your doctor if you are worried about this.


This treatment can cause constipation. 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.

Rarely, thalidomide can cause your bowel to become blocked. Symptoms of a blocked bowel include:

  • constipation
  • feeling sick or vomiting large amounts
  • a swollen and painful tummy
  • feeling bloated.

If you are worried your bowel may be blocked, contact the hospital immediately.

Build-up of fluid

Your ankles, legs or hands may swell because of fluid building up. Tell your doctor or nurse if this happens, as there are medicines that can help. If the swelling is uncomfortable, they may prescribe support stockings. The swelling gets better after your treatment ends.

Feeling sick

This is usually mild. Your doctor can prescribe anti-sickness (anti-emetic) drugs to help prevent or control sickness. If you still feel sick, tell your doctor as they can prescribe different anti-sickness drugs that may work better for you.

Dry mouth

You may get a dry mouth. Drink plenty of fluids and add sauces and gravies to your food to keep it moist. If you have dry lips, using a lip balm can help.

Effects on the lungs

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.

Mood changes

Some people taking thalidomide can have a low mood or become anxious. Tell your doctor if you notice any mood changes. 

Shaking (tremor)

Your hands might shake more than usual. Tell your doctor if you notice this. It will get better after your treatment ends.

Skin changes

Your skin may become dry and itchy. You may also notice a rash or redness. Tell your doctor or nurse if you have any of these symptoms. They can prescribe creams and drugs to help.

Rarely, thalidomide can cause a much more serious skin condition. You may have a skin rash that causes peeling and blistering. Contact the hospital straight away if this happens.

Less common side effects of thalidomide

Allergic reaction

Some people may have an allergic reaction to this treatment. Signs include:

  • a skin rash
  • itching
  • wheezing
  • difficulty breathing
  • breathlessness.

Let your nurse or doctor know straight away if you have any of these symptoms. Do not take your next dose until you have spoken to them. 

Seizures (fits)

Thalidomide can cause seizures (fits) in some people. Contact the hospital straight away if this happens.

Heart problems

Sometimes thalidomide can affect the heart. You may notice your heart feels like it is beating too slowly. Let your doctor know if this happens.

Less commonly thalidomide may cause more serious effects on the heart. Contact a doctor straight away if you:

  • have pain or tightness in your chest
  • feel breathless or dizzy
  • feel your heart is beating too fast or too slowly or is irregular.

Other conditions can cause these symptoms, but it is important to get them checked by a doctor. 

Blood clot risk

This treatment can increase the risk of a blood clot. Symptoms of a blood clot include:

  • pain, redness or swelling in a leg or arm
  • breathlessness
  • chest pain.

If you have any of these symptoms, contact a doctor straight away.

A blood clot is serious, but can be treated with drugs that thin the blood. Your doctor or nurse can give you more information.

A blood clot can increase the risk of having a stroke. Signs of a stroke include:

  • weakness or numbness in one side of your body
  • slurred speech or drooping of your face, mouth or eye
If you, or someone you know, notices you have any of these symptoms, get medical advice straight away.

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. They will also test you for hepatitis B before you have this treatment.

Other information

Other drugs

Some medicines, including ones you buy in a shop or chemist, can be harmful while you are having this treatment. Tell your cancer doctor about any drugs you are taking, including vitamins, herbal drugs and complementary therapies.


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.

Medical and dental treatment

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.


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 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, such as shingles, 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.