Dosing and uses of Mesnex (mesna)
Adult dosage forms and strengths
injectable solution
- 100mg/mL
tablet
- 400mg
With Ifosfamide
240 mg/sq.meter (if receiving 1.2 g/sq.meter ifosfamide dose) IVP 15 minutes before & 4 & 8 hours after ifosfamide admin Or
240 mg/sq.meter (if receiving 1.2 g/sq.meter ifosfamide dose) IVP 15 minutes before & 480 mg/sq.meter PO 2 & 6 hours after ifosfamide admin
Adjust dose accordingly if ifosfamide dose changes
Also given by alternative IVP regimens, intermittent infusion or continuous infusion-see IV Info
With Cyclophosphamide (Off-label)
60-160% of cyclophosphamide daily dosage divided 3-5 doses IVP OR by continuous IV infusion
Other Indications & Uses
Ifosfamide-induced hemorrhagic cystitis
Off-label: Cyclophosphamide-induced hemorrhagic cystitis
Pediatric dosage forms and strengths
Safety & efficacy not established
Mesnex (mesna) adverse (side) effects
>10%
Nausea (>50%)
Vomiting (29%)
Anorexia
Asthenia
Fatigue
Fever
Abdominal pain
Constipation
Anemia
Granulocytopenia
Leukopenia
Thrombocytopenia
Alopecia
1-10%
Anxiety
Confusion
Dizziness
Headache
Insomnia
Pain
Somnolence
Chest pain
Edema
Flushing
Tachycardia
Cough
Dyspnea
Pneumonia
Diarrhea
Hematuria
Hypokalemia
Back pain
Dehydration
Injection site reaction
Pallor
Warnings
Contraindications
Hypersensitivity to mesna or other thiol compounds
Cautions
Does NOT prevent nephrotoxicity, myelosuppression, or neurotoxicity
Contains benzyl alcohol as preservative ( associated w/ potentially fatal "Gasping Syndrome" in preemies)
If pt vomits within 2 hr after PO dose, repeat dose or give IV
Pregnancy and lactation
Pregnancy category: B
Lactation: not known if excreted in breast milk, do not nurse
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Mesnex (mesna)
Half-Life:
Mesna: 0.36 hr
Dimesna: 1.17 hr
Peak Plasma
Time
- Mesna: 4 hr
- Dimesna: 3 hr
Concentration:
- Mesna: 3.3 mcg/mL (PO)
- Dimesna: 7.3 mcg/mL (PO)
Other Information
Bioavailability: 76%
Protein Bound: 69-75% (mesna+dimesna)
Vd: 0.65 L/kg
Metabolism: kidney
Metabolites: mesna disulfide
Excretion: urine
Mechanism of action
Mesna: synthetic sulfhydryl (thiol) compound: binds & detoxifies ifosfamide metabolites in bladder/kidney
Mesna disulfide (dimesna): inert metabolite
Administration
IV Incompatibilities
Additive: carboplatin, cisplatin, ifosfamide/epirubicin
Syringe: ifosfamide/epirubicin
Y-site: amphotericin B cholesteryl sulfate
IV Compatibilities
Solution: D5W, NS, LR, D5/½Ns
Additive: ifosfamide, hydroxyzine
Syringe: ifosfamide
Y-site (partial list): allopurinol, docetaxel, gemcitabine, doxorubicin liposomal, linezolid, granisetron, ondansetron, vinorelbine
IV Preparation
Reconstitute w/ D5W, NS, dextrose/saline or LR to a final concentration of 20 mg/mL
IV Administration
IVP: bolus 15 min before ifosfamide
Intermittent infusion over 15-30 min
Continuous Infusion: may be added to ifosfamide/cyclophosphamide in infusion bag
- Additive compatibility w/ cyclophosphamide shown only in D5W & LR
Multiple protocols exist; check institutional guidelines
Storage
Store unopened vials at 20-25°C (68-77°F)
Opened ampoules will oxidize to dimesna upon exposure to air
