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Trade/other name(s): Mesnex, sodium-2-mercaptoethane sulfonate

Why would this drug be used?

Mesna, a member of a group of drugs known as cytoprotective (cell-protecting) agents, is used to help reduce the risk of bladder damage caused by certain chemotherapy drugs such as ifosfamide or cyclophosphamide.

How does this drug work?

The chemotherapy drugs ifosfamide and cyclophosphamide are normally removed from the bloodstream by the kidneys and broken down into other compounds. These compounds can damage the lining of the bladder and cause blood in the urine, a condition known as hemorrhagic cystitis. Mesna works by binding to these compounds, making them less toxic. They are then excreted from the body in the urine.

Before taking this medicine

Tell your doctor…

  • If you are allergic to any medicines, dyes, additives, or foods.
  • If you have any medical conditions such as kidney disease, liver disease (including hepatitis), heart disease, congestive heart failure, lung disease, diabetes, gout, or infections. You may need closer monitoring of these conditions while being treated, or the drug dose, regimen, or timing may need to be changed.
  • If you have any autoimmune illnesses such as rheumatoid arthritis or systemic lupus erythematosus. You may be more likely to have an allergic reaction to mesna.
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. There may be an increased risk of harm to the fetus if a woman takes this drug during pregnancy. This drug should be used during pregnancy only if the potential benefit is thought to justify the potential risk to the fetus.
  • If you are breast-feeding. While no studies are available, this drug may pass into breast milk and affect the baby. Talk with your doctor about the possible risks of breast-feeding while taking this drug.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

No serious interactions with other drugs are known at this time. But this does not necessarily mean that none exist. Check with your doctor, nurse, or pharmacist about all of your medicines, herbs, and supplements, and whether alcohol can cause problems with this medicine.

Interactions with foods

No serious interactions with food are known at this time. Check with your doctor, nurse, or pharmacist about whether some foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Mesna is given either as an injection into a vein (intravenous, or IV) or by mouth as a pill. It is usually given in 3 doses on each day that ifosfamide is given. The first dose is given IV at the same time as ifosfamide. The second and third doses, which can be either IV or by mouth, are given several hours later. It may also be given as a single long-term IV infusion over many hours. The dose and timing depend on several factors: your body size, the amount of chemotherapy you are getting, and the way the drug is being given.

It is very important to take mesna as prescribed by your doctor. If you have vomiting within 2 hours of taking mesna by mouth, call your doctor right away, as you may need to repeat the dose or be given the mesna as an IV injection.

Store pills in a tightly closed container away from heat and moisture and out of the reach of children and pets.


While mesna works for most people, some people may still have blood in their urine while taking it. Your doctor will likely check your urine frequently for any signs of blood. Tell your doctor or nurse right away if you have pain or burning when urinating or if you notice that your urine has turned red or pink.

It is important to drink plenty of fluids on days when you are getting mesna. Ask your doctor or nurse how much you should be drinking.

You may have nausea and vomiting on the day you receive this drug. Your doctor may give you anti-nausea medicine before your treatment to help prevent this. You may also get a prescription for an anti-nausea medicine that you can take at home. It is important to have these medicines on hand and to take them as prescribed by your doctor.

In rare cases, this drug can cause allergic reactions when the drug is given. Mild reactions may consist of fever, chills, skin itching, or feeling flushed. More serious reactions happen rarely, but can be dangerous. Symptoms can include feeling lightheaded or dizzy (due to low blood pressure), chest tightness, shortness of breath, back pain, or swelling of the face, tongue, or throat. Tell your doctor or nurse right away if you notice any of these symptoms during or after being given the drug.

Some people who check their urine for ketones may have false positive results while taking mesna.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.


  • bad taste when taken by mouth (your health care team may recommend taking it with a strong-flavored beverage)
  • nausea or vomiting*

Less common

  • mild diarrhea
  • headache
  • loss of appetite
  • flu-like symptoms (fever, flushing, dizziness)
  • cold symptoms (sore throat, runny nose)
  • feeling tired or sleepy


  • fast heartbeat
  • low blood pressure
  • allergic reaction (may include shortness of breath, wheezing, swelling in the mouth or throat, hives, itching, flushing, or fever)*

*See Precautions section for more detailed information.

There are some other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved in 1988.

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.

Last Medical Review: 10/22/2009
Last Revised: 10/22/2009