A Comparative Analysis of the Urinary Excretion Profiles of Mesna and Argimesna Following Oral Administration to Healthy Volunteers

Mesna, the sodium salt of 2-mercaptoethanesulphonic acid (MES), is a uroprotective agent used to prevent oxazaphosphorine-induced haemorrhagic cystitis during cancer chemotherapy. Oral administration of mesna is frequently associated with nausea and vomiting secondary to its unpleasant taste. Argimesna, a newly synthesised salt of MES in which sodium is replaced by arginine, has not been associated with similar adverse effects. In this study, the urinary excretion of the two salts of MES was compared after oral administration of either mesna 800mg or argimesna 1800mg (equivalent to 920mg of mesna). The 2 drugs exhibited almost identical urinary excretion patterns. Percentage recoveries 12 hours after drug administration were 14.8 and 13.2% of the dose for mesna and argimesna, respectively. Maximum urinary concentrations of free thiols were observed with both drugs during the 0- to 4-hour urine collection, and were 3.9 mmol/L for mesna and 3.3 mmol/L for argimesna. Since 0.61 mmol/L is considered the minimum free thiol concentration required to confer uroprotection, it is concluded that argimesna ensures a uroprotective activity equivalent to that of mesna and may be advantageously substituted for mesna in oral therapeutic regimens.