Combined intravenous and oral mesna in outpatients treated with ifosfamide

Purpose: To prevent hemorrhagic cystitis, mesna is typically injected intravenously (IV) at the time of an ifosfamide dose and 4 and 8 h later. To simplify outpatient ifosfamide therapy, we gave the second and third mesna doses orally. Methods: The mesna doses (400 or 600 mg/m(2)) were 40% (w/w) of each ifosfamide dose (1.0 or 1.5 g/m(2)), which was given daily for 5 days. We evaluated urinary mesna excretion and plasma concentrations in ten patients from the beginning of mesna infusion until the time of the second oral dose. The first oral dose was administered at hour 2 in the last six patients to allow time for absorption of mesna. Results: The rate and amount of mesna excretion was less variable over time and among patients after oral than after IV administration. No macrohematuria was observed in these ten patients nor in an additional 50 patients given oral mesna at hours 2 and 8 during at least two cycles of ifosfamide therapy. Conclusion: These pharmacokinetic and clinical efficacy data support the use of a combined regimen of IV and oral mesna to simplify outpatient ifosfamide administration.