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Mesnex (oral/injection)

Generic name: mesna (oral/injection) [ MEZ-nah ]
Brand name: Mesnex
Drug class: Antineoplastic detoxifying agents

Medically reviewed by on Jan 23, 2023. Written by Cerner Multum.

What is Mesnex?

Mesnex is used to prevent bleeding in the bladder (hemorrhagic cystitis) during chemotherapy with ifosfamide (Ifex).

Mesnex will not prevent other side effects caused by ifosfamide.

Mesnex may also be used for purposes not listed in this medication guide.

Mesnex side effects

Get emergency medical help if you have signs of an allergic reaction or severe skin reaction:

  • fever, nausea, vomiting, joint or muscle pain;

  • hives, rash or redness, skin pain or swelling, blisters or peeling;

  • feeling light-headed, trouble breathing;

  • racing heartbeats; or

  • mouth sores, or swelling in your face or throat.

Mesnex may cause serious side effects. Call your doctor at once if you have:

  • chest pain, trouble breathing;

  • easy bruising or bleeding (nosebleeds, bleeding gums);

  • low red blood cells (anemia)--pale skin, unusual tiredness, feeling light-headed or short of breath, cold hands and feet; or

  • low potassium level--leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling.

Common side effects of Mesnex may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Get emergency medical help if you have signs of a serious reaction: fever, nausea, vomiting, racing heartbeats, hives, rash or redness, skin pain or swelling, blisters or peeling, joint or muscle pain, feeling light-headed, trouble breathing, mouth sores, or swelling in your face or throat.

Before taking this medicine

You should not use Mesnex if you are allergic to Mesnex, edetate sodium, sodium hydroxide, or benzyl alcohol.

Tell your doctor if you are allergic to any medicine.

Although Mesnex is not expected to harm an unborn baby, ifosfamide can harm an unborn baby if the mother or the father is using this medicine.

  • If you are a woman, you may need to have a negative pregnancy test before starting this treatment with ifosfamide. Use effective birth control to prevent pregnancy while you are using ifosfamide and for at least 6 months after your last dose.

  • If you are a man, use effective birth control if your sex partner is able to get pregnant. Keep using birth control for at least 3 months after your last dose of ifosfamide.

  • Tell your doctor right away if a pregnancy occurs while either the mother or the father is using ifosfamide.

Do not breast-feed while using Mesnex or ifosfamide, and for at least 1 week after your last dose.

Mesnex injection contains an ingredient that can cause serious side effects or death in premature or low-birthweight babies. This medicine tablets do not contain this ingredient. This medicine injection should not be given to a premature or low birth weight infant.

How is Mesnex given?

Before and during treatment with Mesnex, you may need frequent urine tests.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Mesnex injection is given as an infusion into a vein. A healthcare provider will give you this injection at the same time you receive ifosfamide.

Oral Mesnex is taken by mouth, usually 2 and 6 hours after you receive ifosfamide.

Mesnex is given either in a series of 3 injections spaced 4 hours apart, or as a single injection followed by 2 oral doses spaced 2 and 6 hours later.

Follow your doctor's dosing instructions very carefully.

Call your doctor if you vomit within 2 hours after taking oral Mesnex. You may need to take another oral dose or receive a this medicine injection.

Tell your doctor if you have red or pink colored urine. This may be a sign that your ifosfamide dose needs to be changed.

Drink at least 1 to 2 liters (32 to 64 ounces) of liquid each day while you are using Mesnex.

This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using Mesnex.

Store Mesnex tablets at room temperature away from moisture and heat.

What happens if I miss a dose?

Call your doctor for instructions if you miss a dose of Mesnex.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using Mesnex?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect Mesnex?

Other drugs may affect Mesnex, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.