Mesna

  Action Mesna is used to reduce the incidence of ifosfamide-induced hemorrhagic cystitis. The mesna disulfide is reduced to the free thiol compound, which reacts chemically with the urotoxic ifosfamide metabolites resulting in their detoxification. At doses of 2 to 4 g the terminal elimination half-life is approximately 7 hr. It is rapidly eliminated by the kidneys.

  Indications Prevention of ifosfamide-induced hemorrhagic cystitis.

Prevention of cyclophosphamide-induced hemorrhagic cystitis.

  Contraindications Standard considerations.

  Route/Dosage

Prevention of Ifosfamide-Induced Hemorrhagic Cystitis

Adults: IV Mesna dose is 20% of ifosfamide dose at time of, 4 hr after, and 8 hr after each ifosfamide dose (eg, for ifosfamide 1200 mg/m2, give mesna 240 mg/m2 at 0, 4, and 8 hr after each ifosfamide dose). The total daily dose of mesna is 60% of the ifosfamide dose. Repeat this dosing schedule on each day that ifosfamide is administered. When the dosage of ifosfamide is adjusted, modify the dose of mensa accordingly. Some clinicians recommend giving additional mesna at the same infusion rate for 8 to 24 hr after the ifosfamide infusion finishes.

Adults: PO Following the initial IV mesna dose (20% of ifosfamide dose), the oral mesna dose is 40% of ifosfamide dose 2 and 6 hr after each ifosfamide dose.

  Interactions None well documented.

  Lab Test Interferences A false positive test for urinary ketones may arise in patients treated with mesna.

  Adverse Reactions

DERMATOLOGIC: Macular rash; pruritus. GI: Nausea; vomiting; diarrhea; soft stools; dysgeusia. GU: Hematuria. HYPERSENSITIVITY: Severe allergic reactions consisting of fever, tachycardia, and macular rash.

  Precautions

Pregnancy: Category B. Lactation: Excretion in breast milk is unknown. Benzyl alcohol: Benzyl alcohol, contained in this product as a preservative, has been associated with a fatal “gasping syndrome” in premature infants. Hematuria: Mesna does not prevent hemorrhagic cystitis in all patients. Up to 6% treated have developed hematuria (more than 50 rbc/hpf or WHO grade 2 and above). Hypersensitivity reactions: Allergic reactions were reported ranging from mild hypersensitivity to systemic anaphylactic reactions. Ifosfamide toxicities: Mesna prevents ifosfamide-induced hemorrhagic cystitis. It will not prevent or alleviate other adverse reactions or toxicities associated with ifosfamide therapy.

  Administration/Storage

• Store at room temperature.
• Dilute IV solution to final concentration of 20 mg/mL with any of the following: 5% Dextrose, 5% Dextrose with 0.45% Sodium Chloride, 0.9% Sodium Chloride, or Lactated Ringer's Solution.
• Diluted solutions of mesna for injection are stable for at least 24 hr at room temperature. Mesna solutions should be discarded after 24 hr. The manufacturer recommends these solutions be refrigerated and used within 6 hr.
• Solutions of mesna for oral use are stable for at least 1 wk at room temperature when stored in capped tubes and diluted in flavored orange or grape syrup. Solutions for oral administration are stable 24 hr at room temperature when further diluted in any of the following: Coca Cola , Dr. Pepper , Pepsi Cola , Sprite , 7-Up , ginger ale, apple juice, or orange juice.
• Mesna oxidizes to inactive form when exposed to air. Store solution for oral use in tightly sealed containers. Discard any unused drug remaining in the ampules and use a new ampule for each administration.
• Mesna is not compatible with cisplatin. Mesna and ifosfamide are compatible in the same infusion fluid.
• Administer by IV bolus or PO.
• If mesna is ever given PO for the initial dose, administer it 1 hr before chemotherapy is given to allow for absorption.

PO

• Dilute solution for injection to 20 or 50 mg/mL with orange or grape syrup. Prior to administration, syrup-diluted solutions may be diluted to a final concentration of 1, 10, or 50 mg/mL with any of the following: Coca Cola , Dr. Pepper , Pepsi Cola , Sprite , 7-Up , ginger ale, apple juice, or orange juice. Dilution of mesna with diet or sugar-free preparations has not been evaluated.

  Assessment/Interventions

• Monitor urinalysis each morning before ifosfamide or cyclophosphamide therapy. If hematuria develops, consider reducing the chemotherapy dose or discontinuing chemotherapy.

  Patient/Family Education

• Explain name, action, and potential side effects of drug.
• Advise patient, family, or caregiver that medication will be prepared and administered by health care provider in a health care setting.
• Review dosing schedule with patient, family, or caregiver.
• Advise patient, family, or caregiver to immediately report any of the following to health care provider: red or pink-colored urine; rash; itching; hives.
• Advise patient, family, or caregiver to report any of the following to health care provider: persistent nausea, vomiting, diarrhea or appetite loss; intolerable “bad taste” in mouth.
• Instruct patient to not take any prescription or OTC medications or dietary supplements unless advised by health care provider.
• Instruct women of childbearing potential to notify helath care provider if they become pregnant, plan on becoming pregnant, or are breastfeeding.
• Advise patient that follow-up visits and laboratory tests will be required to monitor therapy and to be sure to keep appointments.