Urosaph Mechanism of Action

Antineoplastic.
Pharmacology: Pharmacodynamics: Mesna is an antidote that can reliably prevent urotoxic side effects associated with aggressive cancer chemotherapy using oxazaphosphorine cytostatics. Extensive and wide-ranging pharmacological and toxicological investigations have shown that mesna has no intrinsic pharmacodynamics and low toxicity. The pharmacological and toxicological inertness of mesna administered systemically and its excellent detoxifying effect in the efferent urinary tract and bladder, are due to the nature of its pharmacokinetics.
Pharmacokinetics: Mesna, a free thiol, is easily and rapidly transformed by auto-oxidation into its only metabolite mesna-disulfide (dimesna). Dimesna remains in the intravascular compartment and is quickly transported to the kidneys.
In the epithelium of renal tubule, dimesna is again reduced to the free thiol compound, which is then able to react chemically in the urine with toxic oxazaphosphorine metabolites.
Elimination (being almost exclusively renal) starts immediately after administration. Excretion is as the free thiol (mesna) in the first 4 hours after a single dose, and almost exclusively as the disulfide (dimesna) thereafter. Renal elimination is almost complete after approximately 8 hours.
Approximately 30% of an intravenous dose is bioavailable as free thiol (mesna) in the urine.