What is temsirolimus?

Temsirolimus is a targeted therapy drug used to treat kidney (renal) cancer that has spread, and mantle cell lymphoma that has come back after treatment. It may sometimes be used to treat other cancers. It is best to read this information with our general information about targeted therapies and the type of cancer you have.

How temsirolimus works

Temsirolimus is a type of treatment called an mTOR inhibitor, also known as a cancer growth inhibitor. mTOR is a protein inside cells that makes them divide and grow. In cancer cells, this protein is overactive.

Temsirolimus works by blocking (inhibiting) the mTOR protein. This may help to stop the cancer growing or slow down its growth.

Temsirolimus can also stop the cancer cells from making new blood vessels. This reduces their supply of oxygen and nutrients, so that the tumour shrinks or stops growing.

When temsirolimus is given

Temsirolimus can be used to treat people with some types of kidney cancer that has spread (advanced cancer). It may also be used to treat people with mantle cell lymphoma that has come back after chemotherapy or that has not responded to chemotherapy.

The National Institute for Health and Care Excellence (NICE) gives advice on which new drugs or treatments should be available on the NHS in England and Wales. The Scottish Medicines Consortium (SMC) makes recommendations on the use of new drugs within the NHS in Scotland. NICE and the SMC do not recommend the use of temsirolimus for kidney cancer or for mantle cell lymphoma. Northern Ireland endorses NICE guidance for temsirolimus.

As a result, temsirolimus may not be widely available on the NHS. But you may be given it as part of a clinical trial.

Speak to your doctor to see if temsirolimus is recommended for the type of cancer you have.

How temsirolimus is given

During treatment, you usually see a cancer doctor, a chemotherapy nurse or a specialist nurse. This is who we mean when we mention doctor or nurse in this information.

Before or on the day of treatment, a nurse or person trained to take blood (phlebotomist) will take a blood sample from you. This is to check that your blood cells are at a safe level to have treatment.

You will see a doctor or nurse before you have temsirolimus. They will ask you how you have been feeling. If your blood results are okay, the pharmacist will prepare your treatment. Your nurse will tell you when it is likely to be ready.

Your nurse gives you anti-sickness drugs before you start treatment. Temsirolimus is then given in one of the following ways:

  • through a short thin tube (cannula), which the nurse puts into a vein in your arm or hand
  • through a fine tube that goes under the skin of your chest and into a vein close by (central line)
  • through a fine tube that is put into a vein in your arm and goes up into a vein in your chest (PICC line).

Temsirolimus is given as a drip into a vein (intravenous infusion). Each infusion takes 30 to 60 minutes. It is usually given once a week. The number of doses you have will depend on how well it is working and on how any side effects affect you. Talk to your doctor or specialist nurse about how many treatments you will have.

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.

Side effects during treatment

Some people may have side effects while they are being given the treatment or shortly after they have it:

Allergic reaction

Some people have an allergic reaction while having this treatment. Signs of a reaction can include:

  • feeling hot or flushed
  • a skin rash
  • itching
  • shivering
  • feeling dizzy
  • a headache
  • feeling breathless
  • swelling of your face or mouth
  • pain in your back, tummy or chest.

Your nurse will check you for signs of a reaction during your treatment. If you feel unwell or have any of these signs, tell them straight away. If you do have a reaction, it can be treated quickly.

Sometimes a reaction can happen a few hours after treatment. If you get any signs or feel unwell after you get home, contact the hospital straight away.

Common side effects

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 called neutropenia.

If you have an infection, it is important to treat it as soon as possible. Contact the hospital straight away on the 24-hour contact number you have 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.

Symptoms of an infection include:

  • feeling shaky
  • a sore throat
  • a cough
  • diarrhoea
  • needing to pass urine a lot.

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

The number of white blood cells 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.

Bruising and bleeding

Temsirolimus can reduce the number of platelets in your blood. Platelets are cells that help the blood to clot. Tell your doctor if you have any bruising or bleeding that you can’t explain. This includes:

  • nosebleeds
  • bleeding gums
  • tiny red or purple spots on the skin that may look like a rash.

Some people may need a drip to give them 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. These cells carry oxygen around the body. If the number of red blood cells is low, you may be tired and breathless. Tell your doctor or nurse if you feel like this.

If you are very anaemic, you may need a drip to give you extra blood cells. This is called a blood transfusion.

Feeling tired

Feeling tired is a common side effect. It is often worse towards the end of treatment and for some weeks after it has finished. 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.

Skin changes

This treatment may affect your skin. It can cause a rash, which may be itchy. Your doctor or nurse can tell you what to expect. If your skin feels dry, try using an unperfumed moisturising cream every day.

Always tell your doctor or nurse about any skin changes or if they get worse. 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.

Sore mouth

You may get a sore mouth or mouth ulcers. This can make you more likely to get a mouth infection.

Use a soft toothbrush to clean your teeth or dentures in the morning, at night and after meals.

If your mouth is sore:

  • tell your nurse or doctor – they can give you a mouthwash or medicines to help
  • try to drink plenty of fluids
  • avoid alcohol, tobacco, and foods that irritate your mouth.

Loss of appetite

This treatment can affect your appetite. Do not worry if you do not eat much for a day or two. But if your appetite does not come back after a few days, tell your nurse or dietitian. They will give you advice. They may give you food or drink supplements.

Feeling sick

You may feel sick in the first few days after this treatment. Your doctor will give you anti-sickness drugs to help prevent or control sickness. Take the drugs exactly as your nurse or pharmacist tells you. It is easier to prevent sickness than to treat it after it has started.

If you feel sick, take small sips of fluids and eat small amounts often. If you continue to feel sick, or if you vomit more than once in 24-hours, contact the hospital as soon as possible. They will give you advice and may change the anti-sickness drug to one that works better for you.

Changes to your taste

You may get a bitter or metallic taste in your mouth. Sucking sugar-free sweets may help with this. Some foods may taste bad or have no taste. Try different foods to find out what tastes best to you. Your nurse can give you more advice.


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

If you have diarrhoea:

  • try to drink at least 2 litres (31/2 pints) of fluids each day
  • avoid alcohol, caffeine, milk products, high-fat foods and high-fibre foods
  • contact the hospital for advice.

Effects on the lungs

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

  • a cough
  • wheezing
  • a fever (high temperature)
  • breathlessness.

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

Fluid build-up

Some people develop swelling around the eyes, ankles or other areas of their body because of a build-up of fluid. This is not harmful, but it can be upsetting and uncomfortable. Diuretics (drugs that make you pass more urine) can help get rid of some of the fluid, but it often goes away by itself. Let your doctor know if you put on a lot of weight very quickly. This can be a sign that you have fluid build-up.

Raised blood sugar

Temsirolimus may cause a temporary increase in the level of sugar in your blood. Your blood sugar levels will be checked by regular blood tests. Signs of a raised blood sugar level are:

  • feeling thirsty
  • needing to pass urine more often
  • feeling hungry.

If you get any of these symptoms, let your doctor or nurse know.

If you are diabetic, you may need to check your blood sugars more regularly. Talk to your doctor or nurse about how to manage this. You may have to adjust your insulin or tablet dose.

Muscle and joint pain

You may notice that you have back pain, sore muscles and joints. Let your doctor know if you get these side effects, as they can prescribe painkillers.

Difficulty sleeping

Temsirolimus can cause sleeplessness (insomnia) in some people. If you are finding it difficult to sleep, talk to your doctor or specialist nurse.

Less common side effects

Abdominal (tummy) pain

Some people have pain or discomfort in their tummy during treatment with temsirolimus. Let your doctor know if this happens to you. It can usually be controlled with painkillers.

Temsirolimus can cause a hole (perforation) in the small bowel, but this is not common. Contact your doctor immediately if you have severe pain in the tummy or signs of bleeding. This includes bleeding from the back passage, black stools or vomiting up blood (or vomit that looks like coffee grounds).

Effects on the heart

This treatment can affect your heart. You may have tests to see how well your heart is working. Contact a doctor straight away if you:

  • feel breathless or dizzy
  • feel breathless when you lie down
  • have pain or tightness in your chest.

Other conditions can cause these symptoms, but it is important to get them checked by a doctor. If the treatment is causing heart problems, your doctor can change the type of treatment you are having.

Changes to your blood cholesterol

The level of cholesterol in your blood may rise. Your doctor will take blood samples regularly to check this.

Problems with wound healing

Wounds may take longer to heal during treatment with temsirolimus. If you have any surgery planned, you may need to stop having temsirolimus before the operation and not start it again for a few weeks afterwards. Talk to your doctor if you have surgery planned.

It is important to let your doctor know straight away if you feel unwell or have any severe side effects, even if they are not mentioned above.

Other information


This treatment contains alcohol. If this is a problem for you, tell your doctor, nurse or pharmacist. Your blood alcohol level may be above the legal limit after you have the treatment. It is best not to drive or operate machinery for a few hours after having this treatment, even if you feel okay.

Food and drink

You should not have grapefruit or grapefruit juice with temsirolimus. It may increase the amount of temsirolimus in your blood.

Blood clots

This treatment can increase the chances of a blood clot. A clot can cause:

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

Contact your doctor straight away if you have any of these symptoms. A blood clot is serious, but your doctor can treat it with drugs that thin the blood. Your doctor or nurse can give you more 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.


Doctors do not yet know how this treatment may affect your fertility (the ability to get pregnant or make someone pregnant). If you are worried about this, talk to your doctor before your treatment starts.


Your doctor will advise you not to get pregnant or make someone pregnant while having this treatment and for some time afterwards. The drugs may harm the developing baby. It is important to use effective contraception.


Women are advised not to breastfeed while having this treatment. This is because the drugs could be passed to the baby through breast milk.

Medical and dental treatment

If you need medical treatment for any reason other than cancer, always tell the doctors and nurses that 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 this treatment.

How we can help

How to print a PDF from this website
Instructions on how you can make a PDF version of this page using the print function on your browser.
Clinical Information Nurse Specialists
Our Cancer Information Nurse Specialists are dedicated cancer nurses available to talk to on our Macmillan Cancer Support Line. 
0808 808 00 00
7 days a week, 8am - 8pm
Email us
Get in touch via this form
Chat online
7 days a week, 8am - 8pm
Online Community
An anonymous network of people affected by cancer which is free to join. Share experiences, ask questions and talk to people who understand.
Help in your area
What's going on near you? Find out about support groups, where to get information and how to get involved with Macmillan where you live.