Mesna is a drug that is given with the chemotherapy drug ifosfamide, and sometimes with the chemotherapy drug cyclophosphamide. This should ideally be read with our information about ifosfamide or cyclophosphamide.

These drugs can irritate the lining of the bladder and cause bleeding from the lining. Mesna protects your bladder. Drinking plenty of fluid will also help protect your bladder.

Your chemotherapy nurse will usually give you mesna as a drip (infusion) into a vein at the same time as your chemotherapy. You can also take it by mouth, either as tablets or as a liquid to drink. It is important to take mesna as directed by your doctor.

Like other drugs, mesna can cause side effects. If these happen they are usually mild but occasionally can be severe. It is important to read the detailed information below so that you are aware of possible side effects. Tell your doctor or nurse if you notice any changes.

Why mesna is given

If you are given ifosfamide chemotherapy, you may get blood in your urine (haematuria). This can also happen with higher doses of cyclophosphamide chemotherapy. Both drugs can cause irritation and bleeding from the lining of the bladder. Mesna helps prevent this by protecting your bladder lining.

Mesna is always given with ifosfamide and is normally given with higher doses of cyclophosphamide. While you're having this treatment, your urine is measured and tested for any signs of blood. If you have blood in your urine, you’ll be given extra mesna. Drinking plenty of water and emptying your bladder often during the treatment will also help to protect your bladder lining.

How mesna is given

Mesna is a clear fluid. It is usually given as a drip (infusion) at the same time as your chemotherapy. The infusion will be given through a fine tube (cannula) put into a vein. This is removed after each treatment.

You may be given mesna and chemotherapy through a fine plastic tube that is placed under the skin and into a vein near the collarbone (a central line). It may also be passed through a vein in your arm (a PICC line). Central and PICC lines stay in and are taken out after all your treatments have finished. Your doctor or nurse can explain more about this to you.

You can also have mesna by mouth, as a liquid. You can add the mesna to a flavoured soft drink, such as orange juice or cola, to help it taste nicer. It can be kept in a refrigerator for up to 24 hours after mixing. Your doctor, nurse or pharmacist can explain more about this to you.

Mesna is also sometimes taken as a tablet. If you’re given tablets, it's important to take them as directed by your doctor. They can be taken with food or on an empty stomach.

Possible side effects of mesna

We explain the most common side effects of mesna here. But we don’t include rarer ones. For more detailed information you can visit the electronic Medicines Compendium (eMC) at

It is often difficult to know which side effects may be from mesna and which ones may be from the chemotherapy. Always tell your doctor or nurse about the side effects you have. Your nurse will give you telephone numbers for the hospital. You can call them if you feel unwell or need advice any time of day or night. Save these numbers in your phone or keep them somewhere safe.

Side effects from mesna may include:

Allergic reactions

Rarely, mesna may cause an allergic reaction. Your nurse will check you for this. If you have a reaction, they will treat it quickly. Allergic reactions are most common with the first few doses. A reaction is usually mild. Rarely, it can be more severe.

Signs of an allergic reaction can include:

  • faster heartbeat
  • swelling in your face
  • skin reactions
  • breathlessness
  • pain in your back, tummy or chest
  • a rash or bruising on your skin
  • flu-like symptoms such as a headache, feeling flushed, having a fever, chills or dizziness.

Tell your nurse straight away if you notice any of these symptoms.

Rarely, people may have a reaction some time after treatment. If you develop any of these symptoms or feel unwell after you get home, contact the hospital straight away for advice.

Feeling or being sick

Your doctor can prescribe very effective anti-sickness drugs (anti-emetics) to help prevent or reduce sickness. If you are sick after taking mesna by mouth, contact the hospital for advice. It’s important you don’t miss a dose of mesna so that your bladder lining is protected.

Taste changes

You may get a bitter or metallic taste in your mouth or find that food tastes different. This should go away when your treatment finishes. Try using herbs and spices (unless you have a sore mouth or ulcers) or strong-flavoured sauces to give your food more flavour. Sucking boiled sweets or chewing gum can sometimes help get rid of a bitter or metallic taste. Your nurse can give you more advice.


Mesna may cause headaches. If this happens, let your doctor or nurse know. They can give you painkillers.

Tummy pain

You may get pain or discomfort in your tummy (abdomen), feel bloated or wind. Your doctor can prescribe drugs to help improve these symptoms. Tell them if the pain doesn’t improve or gets worse.


Your doctor can prescribe drugs to control diarrhoea. Let them know if it is severe or if it doesn’t get better. Make sure you drink at least two litres (three and a half pints) of fluids every day if you have diarrhoea.


Feeling very tired is a common side effect. It’s often worse towards the end of treatment and for some weeks after it’s finished. Try to pace yourself and get as much rest as you need. It helps to balance this with some gentle exercise, such as short walks. If you feel sleepy, don’t drive or operate machinery.

Limb and joint pain

You may get pain in your joints or limbs for a few days after treatment. Tell your doctor if this happens so they can prescribe painkillers. Let them know if the pain does not get better. Try to get plenty of rest. Taking regular warm baths may help.

Skin changes

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

Mood and behaviour changes

Occasionally, mesna can affect your mood. You may feel irritable and have mood swings. Tell your doctor or nurse if you have any of these side effects. They may make some changes to your treatment if the side effects become a problem.

Other medicines

Some medicines can affect chemotherapy or be harmful when you are having it. This includes medicines you can buy in a shop or chemist. Tell your cancer doctor about any drugs you are taking, including vitamins, herbal drugs and complementary therapies.