Mesna
Say it: MES-nuh · Brand names: Mesnex
Mesna is a medicine that protects your bladder from damage caused by some chemotherapy.
What it is
The chemotherapy ifosfamide makes a substance that can irritate the bladder lining and cause bleeding. Mesna travels to the bladder and binds to this substance. This makes it harmless before it can cause damage.
Often used for
- protecting the bladder during treatment with ifosfamide
- protecting the bladder with high doses of cyclophosphamide (a common use not on the FDA label)
How you get it
It is given as a drip into a vein, and sometimes as pills by mouth. It is given before, during, and after the chemotherapy, often over the same day or days. Your schedule may be different.
Common side effects and what helps
- Nausea or throwing up. Ask your team about nausea medicine.
- Headache. Ask your team which pain medicine is safe.
- Feeling tired. Rest when you need to.
- Belly pain or constipation. Drink fluids.
- Flushing or a warm feeling. Tell your nurse.
- Pain or redness where the drip goes in. Tell your nurse.
Call your care team right away if you have
- Blood in your urine, or pink or red urine
- Pain or burning when you pee, or peeing much more or less than usual
- Signs of an allergic reaction, like a rash all over, swelling of the face or throat, or wheezing
- A rash with fever, blisters, or peeling
- Throwing up within 2 hours of taking a mesna pill
- A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher
Before you start, tell your team
- If you have had a reaction to mesna or to medicines that contain sulfur groups (thiols)
- If you have an autoimmune disease like lupus
- All medicines you take
- If you are pregnant, may become pregnant, or are breastfeeding
Good to know
- Mesna does not prevent all bladder problems. Your team will check your urine for blood.
- Drink plenty of fluids, at least 4 cups a day or more if your team says so, and pee often.
- Mesna can cause a false positive result on urine tests for ketones.
- Serious allergic and skin reactions are rare but can happen.
At home
- If you take mesna pills, take them at the exact times your team gave you.
- If you throw up within 2 hours of a pill, call your team. You may need another dose.
- Drink plenty of fluids and empty your bladder often, including at night if your team tells you.
- Store at room temperature, away from children.
Questions to ask
- How much fluid should I drink each day?
- Will I take mesna pills at home?
- What should I do if I see blood in my urine?
Part of these treatment plans
Side effect guides
Sources
Quick answers
- What is Mesna?
- Mesna is a medicine that protects your bladder from damage caused by some chemotherapy. Brand names: Mesnex.
- What is Mesna used for?
- protecting the bladder during treatment with ifosfamide; protecting the bladder with high doses of cyclophosphamide (a common use not on the FDA label).
- How is Mesna given?
- It is given as a drip into a vein, and sometimes as pills by mouth. It is given before, during, and after the chemotherapy, often over the same day or days. Your schedule may be different.
- What are the common side effects of Mesna?
- Nausea or throwing up. Headache. Feeling tired. Belly pain or constipation. Flushing or a warm feeling. Pain or redness where the drip goes in.
- When should I call my care team while taking Mesna?
- Blood in your urine, or pink or red urine; Pain or burning when you pee, or peeing much more or less than usual; Signs of an allergic reaction, like a rash all over, swelling of the face or throat, or wheezing; A rash with fever, blisters, or peeling; Throwing up within 2 hours of taking a mesna pill; A fever of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher.
- Which chemotherapy plans include Mesna?
- AIM, Hyper-CVAD, RICE, VAC/IE, VIP.
Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.