Overview
11 DESCRIPTION MESNEX (mesna) is a detoxifying agent to inhibit the hemorrhagic cystitis induced by ifosfamide. The active ingredient, mesna, is a synthetic sulfhydryl compound designated as sodium-2-mercaptoethane sulfonate with a molecular formula of C 2 H 5 NaO 3 S 2 and a molecular weight of 164.18.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Mesna reacts chemically with the urotoxic ifosfamide metabolites, acrolein and 4-hydroxy-ifosfamide, resulting in their detoxification. The first step in the detoxification process is the binding of mesna to 4-hydroxy-ifosfamide forming a non-urotoxic 4-sulfoethylthioifosfamide. Mesna also binds to the double bonds of acrolein and to other urotoxic metabolites and inhibits their effects on the bladder. 12.3 Pharmacokinetics Absorption Following oral administration, peak plasma concentrations were reached within 1.5 to 4 hours and 3 to 7 hours for free mesna and total mesna (mesna plus dimesna and mixed disulfides), respectively.
Indications
- 1 INDICATIONS AND USAGE MESNEX is indicated as a prophylactic agent in reducing the incidence of ifosfamide-induced hemorrhagic cystitis. Limitation of Use: MESNEX is not indicated to reduce the risk of hematuria due to other pathological conditions such as thrombocytopenia. MESNEX is a cytoprotective agent indicated as a prophylactic agent in reducing the incidence of ifosfamide-induced hemorrhagic cystitis. ( 1 ) Limitation of Use: MESNEX is not indicated to reduce the risk of hematuria due to other pathological conditions such as thrombocytopenia. ( 1 )
Common Doses
- 1.2 g
- 240 mg
- 480 mg
- 2 g
Dosage
2 DOSAGE AND ADMINISTRATION MESNEX may be given on a fractionated dosing schedule of three bolus intravenous injections or a single bolus injection followed by two oral administrations of MESNEX tablets as outlined below. The dosing schedule should be repeated on each day that ifosfamide is administered. When the dosage of ifosfamide is adjusted, the ratio of MESNEX to ifosfamide should be maintained. ( 2 ) Intravenous Dosing Schedule: 0 Hours 4 Hours 8 Hours Ifosfamide 1.
Contraindications
- 4 CONTRAINDICATIONS MESNEX is contraindicated in patients known to be hypersensitive to mesna or to any of the excipients [see Warnings and Precautions (5.1) ]. Known hypersensitivity to mesna or to any of the excipients, including benzyl alcohol. ( 4 )
Side Effects
- 6 ADVERSE REACTIONS The following are discussed in more detail in other sections of the labeling. Hypersensitivity Reactions [see Warnings and Precautions (5.1) ] Dermatological Toxicity [see Warnings and Precautions (5.2) ] Benzyl Alcohol Toxicity [see Warnings and Precautions (5.3) ] Laboratory Test Interferences [see Warnings and Precautions (5.4) ] Use in Patients with a History of Adverse Reactions to Thiol Compounds [see Warnings and Precautions (5.
Interactions
- 7 DRUG INTERACTIONS No clinical drug interaction studies have been conducted with MESNEX.